media: atomisp: use regulator_get_optional() for first attempt

Some BIOSes seem to use different names for some regulators.

Use regulator_get_optional() for the first attempt, in order
to avoid using the dummy regulator and produce a warning, in
the case that the first attempt fails.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/staging/media/atomisp/platform/intel-mid/atomisp_gmin_platform.c

@@ -405,8 +405,11 @@ static struct gmin_subdev *gmin_subdev_add(struct v4l2_subdev *subdev)
 		gmin_subdevs[i].gpio1 = NULL;
 
 	if (pmic_id == PMIC_REGULATOR) {
-		gmin_subdevs[i].v1p8_reg = regulator_get(dev, "V1P8SX");
-		gmin_subdevs[i].v2p8_reg = regulator_get(dev, "V2P8SX");
+		/* Those regulators may have different names depending on the BIOS */
+		gmin_subdevs[i].v1p8_reg = regulator_get_optional(dev, "V1P8SX");
+		gmin_subdevs[i].v2p8_reg = regulator_get_optional(dev, "V2P8SX");
+
+
 		gmin_subdevs[i].v1p2_reg = regulator_get(dev, "V1P2A");
 		gmin_subdevs[i].v2p8_vcm_reg = regulator_get(dev, "VPROG4B");