media: core: v4l2-ioctl.c: use is_valid_ioctl()

In most cases the is_valid_ioctl() macro is used to check if an ioctl is
valid, except in one place. Use it there as well as it makes the code
easier to read.

Signed-off-by: Hans Verkuil <[e-mail]>

drivers/media/v4l2-core/v4l2-ioctl.c

···
 	if (v4l2_is_known_ioctl(cmd)) {
 		info = &v4l2_ioctls[_IOC_NR(cmd)];
 
-		if (!test_bit(_IOC_NR(cmd), vfd->valid_ioctls) &&
+		if (!is_valid_ioctl(vfd, cmd) &&
 		    !((info->flags & INFO_FL_CTRL) && vfh && vfh->ctrl_handler))
 			goto done;