regmap: Bypass the cache when applying patches

Otherwise any patch that affects a register which is writable may trash
cached values.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

drivers/base/regmap/regcache.c

@@ -273,6 +273,7 @@ int regcache_sync(struct regmap *map)
 		goto out;
 
 	/* Apply any patch first */
+	map->cache_bypass = 1;
 	for (i = 0; i < map->patch_regs; i++) {
 		ret = _regmap_write(map, map->patch[i].reg, map->patch[i].def);
 		if (ret != 0) {
@@ -281,6 +282,7 @@ int regcache_sync(struct regmap *map)
 			goto out;
 		}
 	}
+	map->cache_bypass = 0;
 
 	if (map->cache_ops->sync) {
 		ret = map->cache_ops->sync(map);