media: i2c: imx290: Drop regmap cache

Only two registers are ever read, and once only. There's no need to
cache values.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>

drivers/media/i2c/imx290.c

@@ -97,7 +97,6 @@ static const struct imx290_pixfmt imx290_formats[] = {
 static const struct regmap_config imx290_regmap_config = {
 	.reg_bits = 16,
 	.val_bits = 8,
-	.cache_type = REGCACHE_RBTREE,
 };
 
 static const char * const imx290_test_pattern_menu[] = {