media: v4l: fix uapi mpeg slice params definition

We get a headers_check warning about the newly defined ioctl command
structures:

./usr/include/linux/v4l2-controls.h:1105: found __[us]{8,16,32,64} type without #include <linux/types.h>

This is resolved by including linux/types.h, as suggested by the
warning, but there is another problem: Three of the four structures
have an odd number of __u8 headers, but are aligned to 32 bit in the
v4l2_ctrl_mpeg2_slice_params, so we get an implicit padding byte
for each one. To solve that, let's add explicit padding that can
be set to zero and verified in the kernel.

Fixes: c27bb30e ("media: v4l: Add definitions for MPEG-2 slice format and metadata")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

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

@@ -1664,6 +1664,11 @@ static int std_validate(const struct v4l2_ctrl *ctrl, u32 idx,
 		    p_mpeg2_slice_params->forward_ref_index >= VIDEO_MAX_FRAME)
 			return -EINVAL;
 
+		if (p_mpeg2_slice_params->pad ||
+		    p_mpeg2_slice_params->picture.pad ||
+		    p_mpeg2_slice_params->sequence.pad)
+			return -EINVAL;
+
 		return 0;
 
 	case V4L2_CTRL_TYPE_MPEG2_QUANTIZATION:

include/uapi/linux/v4l2-controls.h

@@ -47,11 +47,11 @@
  *  videodev2.h.
  */
 
-#include <linux/types.h>
-
 #ifndef __LINUX_V4L2_CONTROLS_H
 #define __LINUX_V4L2_CONTROLS_H
 
+#include <linux/types.h>
+
 /* Control classes */
 #define V4L2_CTRL_CLASS_USER		0x00980000	/* Old-style 'user' controls */
 #define V4L2_CTRL_CLASS_MPEG		0x00990000	/* MPEG-compression controls */
@@ -1112,6 +1112,7 @@ struct v4l2_mpeg2_sequence {
 	__u8	profile_and_level_indication;
 	__u8	progressive_sequence;
 	__u8	chroma_format;
+	__u8	pad;
 };
 
 struct v4l2_mpeg2_picture {
@@ -1130,6 +1131,7 @@ struct v4l2_mpeg2_picture {
 	__u8	alternate_scan;
 	__u8	repeat_first_field;
 	__u8	progressive_frame;
+	__u8	pad;
 };
 
 struct v4l2_ctrl_mpeg2_slice_params {
@@ -1144,6 +1146,7 @@ struct v4l2_ctrl_mpeg2_slice_params {
 
 	__u8	backward_ref_index;
 	__u8	forward_ref_index;
+	__u8	pad;
 };
 
 struct v4l2_ctrl_mpeg2_quantization {