regmap: Re-introduce bulk read support check in regmap_bulk_read()

Support for drivers to define bulk read/write callbacks in regmap_config
was introduced by the commit d77e74561368 ("regmap: Add bulk read/write
callbacks into regmap_config"), but this commit wrongly dropped a check
in regmap_bulk_read() to determine whether bulk reads can be done or not.

Before that commit, it was checked if map->bus was set. Now has to check
if a map->read callback has been set.

Fixes: d77e74561368 ("regmap: Add bulk read/write callbacks into regmap_config")
Signed-off-by: Javier Martinez Canillas <[e-mail]>
Reviewed-by: Marek Vasut <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Mark Brown <[e-mail]>

drivers/base/regmap/regmap.c

···
 	if (val_count == 0)
 		return -EINVAL;
 
-	if (map->format.parse_inplace && (vol || map->cache_type == REGCACHE_NONE)) {
+	if (map->read && map->format.parse_inplace && (vol || map->cache_type == REGCACHE_NONE)) {
 		ret = regmap_raw_read(map, reg, val, val_bytes * val_count);
 		if (ret != 0)
 			return ret;