common: Drop flash.h from common header

Move this uncommon header out of the common header.

Fix up some style problems in flash.h while we are here.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/fs/cramfs/cramfs.c b/fs/cramfs/cramfs.c
index 228f599..7ef48bb 100644
--- a/fs/cramfs/cramfs.c
+++ b/fs/cramfs/cramfs.c
@@ -25,6 +25,7 @@
  */
 
 #include <common.h>
+#include <flash.h>
 #include <malloc.h>
 #include <asm/byteorder.h>
 #include <linux/stat.h>