common: Move command functions out of common.h

Move these functions into the command.h header file which is a better fit.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/board/gdsys/p1022/controlcenterd-id.c b/board/gdsys/p1022/controlcenterd-id.c
index d6798bd..04d3809 100644
--- a/board/gdsys/p1022/controlcenterd-id.c
+++ b/board/gdsys/p1022/controlcenterd-id.c
@@ -11,6 +11,7 @@
 #endif
 
 #include <common.h>
+#include <command.h>
 #include <dm.h>
 #include <env.h>
 #include <malloc.h>