media: i2c: ov7740: simplify getting state container

The pointer to 'struct v4l2_subdev' is stored in drvdata via
v4l2_i2c_subdev_init() so there is no point of a dance like:

    struct i2c_client *client = to_i2c_client(struct device *dev)
    struct v4l2_subdev *sd = i2c_get_clientdata(client);

This allows to remove local variable 'client' and few pointer
dereferences.
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/i2c/ov7740.c

@@ -1176,8 +1176,7 @@ static int ov7740_remove(struct i2c_client *client)
 
 static int __maybe_unused ov7740_runtime_suspend(struct device *dev)
 {
-	struct i2c_client *client = to_i2c_client(dev);
-	struct v4l2_subdev *sd = i2c_get_clientdata(client);
+	struct v4l2_subdev *sd = dev_get_drvdata(dev);
 	struct ov7740 *ov7740 = container_of(sd, struct ov7740, subdev);
 
 	ov7740_set_power(ov7740, 0);
@@ -1187,8 +1186,7 @@ static int __maybe_unused ov7740_runtime_suspend(struct device *dev)
 
 static int __maybe_unused ov7740_runtime_resume(struct device *dev)
 {
-	struct i2c_client *client = to_i2c_client(dev);
-	struct v4l2_subdev *sd = i2c_get_clientdata(client);
+	struct v4l2_subdev *sd = dev_get_drvdata(dev);
 	struct ov7740 *ov7740 = container_of(sd, struct ov7740, subdev);
 
 	return ov7740_set_power(ov7740, 1);