rtc: goldfish_rtc_probe should be static

There is no need to export goldfish_rtc_probe().

Fixes: 2d6dc19fd25d ("rtc: driver for Goldfish RTC")
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
diff --git a/drivers/rtc/goldfish_rtc.c b/drivers/rtc/goldfish_rtc.c
index 1ace990..3231eb0 100644
--- a/drivers/rtc/goldfish_rtc.c
+++ b/drivers/rtc/goldfish_rtc.c
@@ -72,7 +72,7 @@
 	return 0;
 }
 
-int goldfish_rtc_probe(struct udevice *dev)
+static int goldfish_rtc_probe(struct udevice *dev)
 {
 	struct goldfish_rtc *priv = dev_get_priv(dev);
 	fdt_addr_t addr;