media: atomisp: check before deference asd variable

The asd->isp was referenced before checking if asd is not
NULL.

This fixes this warning:

	../drivers/staging/media/atomisp/pci/atomisp_cmd.c:5548 atomisp_set_fmt_to_snr() warn: variable dereferenced before check 'asd' (see line 5540)

While here, avoid getting the pipe pointer twice.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/staging/media/atomisp/pci/atomisp_cmd.c

@@ -5525,8 +5525,8 @@ static int atomisp_set_fmt_to_snr(struct video_device *vdev,
 				  unsigned int padding_w, unsigned int padding_h,
 				  unsigned int dvs_env_w, unsigned int dvs_env_h)
 {
-	struct atomisp_sub_device *asd = atomisp_to_video_pipe(vdev)->asd;
 	struct atomisp_video_pipe *pipe = atomisp_to_video_pipe(vdev);
+	struct atomisp_sub_device *asd = pipe->asd;
 	const struct atomisp_format_bridge *format;
 	struct v4l2_subdev_pad_config pad_cfg;
 	struct v4l2_subdev_state pad_state = {
@@ -5537,7 +5537,7 @@ static int atomisp_set_fmt_to_snr(struct video_device *vdev,
 	};
 	struct v4l2_mbus_framefmt *ffmt = &vformat.format;
 	struct v4l2_mbus_framefmt *req_ffmt;
-	struct atomisp_device *isp = asd->isp;
+	struct atomisp_device *isp;
 	struct atomisp_input_stream_info *stream_info =
 	    (struct atomisp_input_stream_info *)ffmt->reserved;
 	u16 stream_index = ATOMISP_INPUT_STREAM_GENERAL;
@@ -5551,6 +5551,8 @@ static int atomisp_set_fmt_to_snr(struct video_device *vdev,
 		return -EINVAL;
 	}
 
+	isp = asd->isp;
+
 	v4l2_fh_init(&fh.vfh, vdev);
 
 	stream_index = atomisp_source_pad_to_stream_id(asd, source_pad);