regmap: Don't attempt block writes when syncing cache on single_rw devices

If the device can't support block writes then don't attempt to use raw
syncing which will automatically generate block writes for adjacent
registers, use the existing _single() block syncing implementation.
Reported-by: NJarkko Nikula <jarkko.nikula@linux.intel.com>
Tested-by: NJarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: NMark Brown <broonie@linaro.org>
Cc: stable@vger.kernel.org

drivers/base/regmap/regcache.c

@@ -698,7 +698,7 @@ int regcache_sync_block(struct regmap *map, void *block,
 			unsigned int block_base, unsigned int start,
 			unsigned int end)
 {
-	if (regmap_can_raw_write(map))
+	if (regmap_can_raw_write(map) && !map->use_single_rw)
 		return regcache_sync_block_raw(map, block, cache_present,
 					       block_base, start, end);
 	else