media: soc_camera/rockchip: Fix the build error

As enable the releated config, hit the below error:

drivers/media/i2c/soc_camera/rockchip/adv_camera_module.c:937:34: error:
    assignment to expression with array type
        timings->exposure_valid_frame =
...

and

drivers/media/i2c/soc_camera/rockchip/tc_camera_module.c:963:34: error:
    assignment to expression with array type
        timings->exposure_valid_frame =
....

Change-Id: I4381cc8aa00bb6a968c01d7537a8942b5715fa5c
Signed-off-by: Caesar Wang <wxt@rock-chips.com>

Author: Caesar-github

drivers/media/i2c/soc_camera/rockchip/adv_camera_module.c

@@ -934,7 +934,7 @@ long adv_camera_module_ioctl(struct v4l2_subdev *sd,
 			adv_timings.fine_integration_time_min;
 
 		if (cam_mod->custom.g_exposure_valid_frame)
-			timings->exposure_valid_frame =
+			timings->exposure_valid_frame[0] =
 				cam_mod->custom.g_exposure_valid_frame(cam_mod);
 		if (cam_mod->exp_config.exp_time)
 			timings->exp_time = cam_mod->exp_config.exp_time;

drivers/media/i2c/soc_camera/rockchip/tc_camera_module.c

@@ -960,7 +960,7 @@ long tc_camera_module_ioctl(struct v4l2_subdev *sd,
 			tc_timings.fine_integration_time_min;
 
 		if (cam_mod->custom.g_exposure_valid_frame)
-			timings->exposure_valid_frame =
+			timings->exposure_valid_frame[0] =
 				cam_mod->custom.g_exposure_valid_frame(cam_mod);
 		if (cam_mod->exp_config.exp_time)
 			timings->exp_time = cam_mod->exp_config.exp_time;