Make the v4l2_input struct be compatible between kernel and user space

For some reason the v4l2_input struct had different sizes on user space and
kernel space, adding this attribute makes the struct to have the same size
on both userspace and kernel and will make the ioctl to have the same number
now.

include/linux/videodev2.h

@@ -806,7 +806,7 @@ struct v4l2_input
 	v4l2_std_id  std;
 	__u32	     status;
 	__u32	     reserved[4];
-};
+} __attribute__((__packed__));
 
 /*  Values for the 'type' field */
 #define V4L2_INPUT_TYPE_TUNER		1