media: atomisp: Make atomisp_g_fmt_cap() default to YUV420

Make atomisp_g_fmt_cap() default to YUV420 so that it matches with what
atomisp_try_fmt_cap() and atomisp_queue_setup() do when they need to
pick a default pixelformat.
Reviewed-by: Andy Shevchenko <andy@kernel.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

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

@@ -959,7 +959,7 @@ static int atomisp_g_fmt_cap(struct file *file, void *fh,
 	if (f->fmt.pix.sizeimage)
 		return 0;
 
-	f->fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV;
+	f->fmt.pix.pixelformat = V4L2_PIX_FMT_YUV420;
 	f->fmt.pix.width = 10000;
 	f->fmt.pix.height = 10000;