common: Move get_ticks() function out of common.h

This function belongs in time.h so move it over and add a comment.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/drivers/spi/uniphier_spi.c b/drivers/spi/uniphier_spi.c
index ef02d07..e47b969 100644
--- a/drivers/spi/uniphier_spi.c
+++ b/drivers/spi/uniphier_spi.c
@@ -7,6 +7,7 @@
 #include <clk.h>
 #include <common.h>
 #include <dm.h>
+#include <time.h>
 #include <linux/bitfield.h>
 #include <linux/io.h>
 #include <spi.h>