board: ge: common: rename ge_common.c to ge_rtc.c

The file only contains RTC related code, so let's name
it accordingly.

Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
diff --git a/board/ge/bx50v3/bx50v3.c b/board/ge/bx50v3/bx50v3.c
index cf76cf7..c6b0af8 100644
--- a/board/ge/bx50v3/bx50v3.c
+++ b/board/ge/bx50v3/bx50v3.c
@@ -35,7 +35,7 @@
 #include <version.h>
 #include <stdlib.h>
 #include <dm/root.h>
-#include "../common/ge_common.h"
+#include "../common/ge_rtc.h"
 #include "../common/vpd_reader.h"
 #include "../../../drivers/net/e1000.h"
 #include <pci.h>