regmap: Do not call regcache_exit from regcache_rbtree_init error path

Calling regcache_exit from regcache_rbtree_init is first of all a layering
violation and secondly will cause double frees. regcache_exit will free buffers
allocated by the core, but the core will also free the same buffers when the
cacheops init callback returns an error. Thus we end up with a double free.
Fix this by not calling regcache_exit but only free those buffers which, have
been allocated in this function.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Acked-by: NDimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

drivers/base/regmap/regcache-rbtree.c

@@ -17,6 +17,7 @@
 
 static int regcache_rbtree_write(struct regmap *map, unsigned int reg,
 				 unsigned int value);
+static int regcache_rbtree_exit(struct regmap *map);
 
 struct regcache_rbtree_node {
 	/* the actual rbtree node holding this block */
@@ -149,7 +150,7 @@ static int regcache_rbtree_init(struct regmap *map)
 	return 0;
 
 err:
-	regcache_exit(map);
+	regcache_rbtree_exit(map);
 	return ret;
 }