arm: remove prototype for get_timer_masked

The interruption support had be removed for ARM architecture and
the function get_timer_masked() is no more used except in some
the timer.c files.

This patch clean each timer.c which implement this function and
remove the associated prototype in u-boot-arm.h

For timer.c, I don't verify if the weak version of get_timer
(in lib/time.c) can be used

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
diff --git a/arch/arm/cpu/armv7/sunxi/timer.c b/arch/arm/cpu/armv7/sunxi/timer.c
index 0f8ab0e..304c1ac 100644
--- a/arch/arm/cpu/armv7/sunxi/timer.c
+++ b/arch/arm/cpu/armv7/sunxi/timer.c
@@ -55,12 +55,7 @@
 }
 
 /* timer without interrupts */
-ulong get_timer(ulong base)
-{
-	return get_timer_masked() - base;
-}
-
-ulong get_timer_masked(void)
+static ulong get_timer_masked(void)
 {
 	/* current tick value */
 	ulong now = TICKS_TO_HZ(read_timer());
@@ -77,6 +72,11 @@
 	return gd->arch.tbl;
 }
 
+ulong get_timer(ulong base)
+{
+	return get_timer_masked() - base;
+}
+
 /* delay x useconds */
 void __udelay(unsigned long usec)
 {