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/lib/hashtable.c b/lib/hashtable.c
index e3be563..b96dbe1 100644
--- a/lib/hashtable.c
+++ b/lib/hashtable.c
@@ -13,6 +13,7 @@
  */
 
 #include <errno.h>
+#include <log.h>
 #include <malloc.h>
 #include <sort.h>