common: Drop log.h from common header

Move this header out of the common header.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/net/rarp.c b/net/rarp.c
index c1d9fca..a676a42 100644
--- a/net/rarp.c
+++ b/net/rarp.c
@@ -6,6 +6,7 @@
 
 #include <common.h>
 #include <command.h>
+#include <log.h>
 #include <net.h>
 #include <net/tftp.h>
 #include "nfs.h"