x86: cbfs: Drop unwanted declaration

The intention here is add a forward declaration, not actually declare a
variable. Fix it.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

include/cbfs.h

@@ -135,7 +135,7 @@ void file_cbfs_get_next(const struct cbfs_cachenode **file);
  */
 const struct cbfs_cachenode *file_cbfs_find(const char *name);
 
-struct cbfs_priv *priv;
+struct cbfs_priv;
 
 /**
  * cbfs_find_file() - Find a file in a given CBFS