bcache: Style/checkpatch fixes

Took out some nested functions, and fixed some more checkpatch
complaints.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
Cc: linux-bcache@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/md/bcache/btree.c

@@ -1021,8 +1021,8 @@ retry:
 		goto err_free;
 
 	if (!b) {
-		cache_bug(c, "Tried to allocate bucket"
-			  " that was in btree cache");
+		cache_bug(c,
+			"Tried to allocate bucket that was in btree cache");
 		__bkey_put(c, &k.key);
 		goto retry;
 	}