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/lib/efi_loader/efi_console.c b/lib/efi_loader/efi_console.c
index a55e4b3..218f7ca 100644
--- a/lib/efi_loader/efi_console.c
+++ b/lib/efi_loader/efi_console.c
@@ -7,6 +7,7 @@
 
 #include <common.h>
 #include <charset.h>
+#include <time.h>
 #include <dm/device.h>
 #include <efi_loader.h>
 #include <env.h>