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/nfs.c b/net/nfs.c
index 72e1018..70d0e08 100644
--- a/net/nfs.c
+++ b/net/nfs.c
@@ -30,6 +30,7 @@
 #include <command.h>
 #include <flash.h>
 #include <image.h>
+#include <log.h>
 #include <net.h>
 #include <malloc.h>
 #include <mapmem.h>