regmap: fix regmap_read_poll_timeout warning about sandbox_timer_add_offset

When fixing sandbox test for regmap_read_poll_timeout(), the
sandbox_timer_add_offset was introduced but only defined in sandbox code
thus generating warnings when used out of sandbox :

include/regmap.h:289:2: note: in expansion of macro 'regmap_read_poll_timeout_test'
regmap_read_poll_timeout_test(map, addr, val, cond, sleep_us, \
  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/spi/meson_spifc.c:169:8: note: in expansion of macro 'regmap_read_poll_timeout'
ret = regmap_read_poll_timeout(spifc->regmap, REG_SLAVE, data,
        ^~~~~~~~~~~~~~~~~~~~~~~~
drivers/spi/meson_spifc.c: In function 'meson_spifc_txrx':
include/regmap.h:277:4: warning: implicit declaration of function 'sandbox_timer_add_offset' [-Wimplicit-function-declaration]

This fix adds a timer_test_add_offset() only defined in sandbox, and
renames the previous sandbox_timer_add_offset() to it.

Cc: Simon Glass <sjg@chromium.org>
Reported-by: Tom Rini <trini@konsulko.com>
Fixes: df9cf1cc08 ("test: dm: regmap: Fix the long test delay")
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/sandbox/include/asm/test.h b/arch/sandbox/include/asm/test.h
index fc52f47..e956a05 100644
--- a/arch/sandbox/include/asm/test.h
+++ b/arch/sandbox/include/asm/test.h
@@ -59,14 +59,6 @@
 
 void sandbox_i2c_eeprom_set_offset_len(struct udevice *dev, int offset_len);
 
-/*
- * sandbox_timer_add_offset()
- *
- * Allow tests to add to the time reported through lib/time.c functions
- * offset: number of milliseconds to advance the system time
- */
-void sandbox_timer_add_offset(unsigned long offset);
-
 /**
  * sandbox_i2c_rtc_set_offset() - set the time offset from system/base time
  *
diff --git a/board/sandbox/sandbox.c b/board/sandbox/sandbox.c
index 397e756..9ca1eca 100644
--- a/board/sandbox/sandbox.c
+++ b/board/sandbox/sandbox.c
@@ -31,7 +31,7 @@
 /* system timer offset in ms */
 static unsigned long sandbox_timer_offset;
 
-void sandbox_timer_add_offset(unsigned long offset)
+void timer_test_add_offset(unsigned long offset)
 {
 	sandbox_timer_offset += offset;
 }
diff --git a/drivers/net/sandbox.c b/drivers/net/sandbox.c
index decce2f..c136392 100644
--- a/drivers/net/sandbox.c
+++ b/drivers/net/sandbox.c
@@ -350,7 +350,7 @@
 	struct eth_sandbox_priv *priv = dev_get_priv(dev);
 
 	if (skip_timeout) {
-		sandbox_timer_add_offset(11000UL);
+		timer_test_add_offset(11000UL);
 		skip_timeout = false;
 	}
 
diff --git a/drivers/timer/sandbox_timer.c b/drivers/timer/sandbox_timer.c
index 6d2b045..5228486 100644
--- a/drivers/timer/sandbox_timer.c
+++ b/drivers/timer/sandbox_timer.c
@@ -14,7 +14,7 @@
 /* system timer offset in ms */
 static unsigned long sandbox_timer_offset;
 
-void sandbox_timer_add_offset(unsigned long offset)
+void timer_test_add_offset(unsigned long offset)
 {
 	sandbox_timer_offset += offset;
 }
diff --git a/include/regmap.h b/include/regmap.h
index 8359c51..3cd7a66 100644
--- a/include/regmap.h
+++ b/include/regmap.h
@@ -274,7 +274,7 @@
 		if (cond) \
 			break; \
 		if (IS_ENABLED(CONFIG_SANDBOX) && test_add_time) \
-			sandbox_timer_add_offset(test_add_time); \
+			timer_test_add_offset(test_add_time); \
 		if ((timeout_ms) && get_timer(__start) > (timeout_ms)) { \
 			__ret = regmap_read((map), (addr), &(val)); \
 			break; \
diff --git a/include/time.h b/include/time.h
index 825991e..9fd0d73 100644
--- a/include/time.h
+++ b/include/time.h
@@ -14,6 +14,14 @@
 unsigned long timer_get_us(void);
 
 /*
+ * timer_test_add_offset()
+ *
+ * Allow tests to add to the time reported through lib/time.c functions
+ * offset: number of milliseconds to advance the system time
+ */
+void timer_test_add_offset(unsigned long offset);
+
+/*
  *	These inlines deal with timer wrapping correctly. You are
  *	strongly encouraged to use them
  *	1. Because people otherwise forget