regmap: Add missing map->bus check

The map->bus can be NULL here, add the missing NULL pointer check.

Fixes: d77e745 ("regmap: Add bulk read/write callbacks into regmap_config")
Reported-by: kernel test robot <[email protected]>
Reported-by: Dan Carpenter <[email protected]>
Signed-off-by: Marek Vasut <[email protected]>
Cc: Dan Carpenter <[email protected]>
Cc: Mark Brown <[email protected]>
To: [email protected]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Mark Brown <[email protected]>

Author: Marek Vasut

drivers/base/regmap/regmap.c

@@ -1839,7 +1839,7 @@ static int _regmap_raw_write_impl(struct regmap *map, unsigned int reg,
 				 map->format.reg_bytes +
 				 map->format.pad_bytes +
 				 val_len);
-	else if (map->bus->gather_write)
+	else if (map->bus && map->bus->gather_write)
 		ret = map->bus->gather_write(map->bus_context, map->work_buf,
 					     map->format.reg_bytes +
 					     map->format.pad_bytes,