btrfs: send: squeeze bitfilelds in fs_path

We know that buf_len is at most PATH_MAX, 4k, and can merge it with the
reversed member. This saves 3 bytes in favor of inline_buf.

Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fb.com>

fs/btrfs/send.c

@@ -53,8 +53,8 @@ struct fs_path {
 			char *end;
 
 			char *buf;
-			int buf_len;
-			unsigned int reversed:1;
+			unsigned short buf_len:15;
+			unsigned short reversed:1;
 			char inline_buf[];
 		};
 		char pad[PAGE_SIZE];