[media] media: videobuf2: Restructure vb2_buffer

Remove v4l2 stuff - v4l2_buf, v4l2_plane - from struct vb2_buffer.

Add new member variables - bytesused, length, offset, userptr, fd,
data_offset - to struct vb2_plane in order to cover all information
of v4l2_plane.
struct vb2_plane {
        <snip>
        unsigned int            bytesused;
        unsigned int            length;
        union {
                unsigned int    offset;
                unsigned long   userptr;
                int             fd;
        } m;
        unsigned int            data_offset;
}

Replace v4l2_buf with new member variables - index, type, memory - which
are common fields for buffer management.
struct vb2_buffer {
        <snip>
        unsigned int            index;
        unsigned int            type;
        unsigned int            memory;
        unsigned int            num_planes;
        struct vb2_plane        planes[VIDEO_MAX_PLANES];
        <snip>
};

v4l2 specific fields - flags, field, timestamp, timecode,
sequence - are moved to vb2_v4l2_buffer in videobuf2-v4l2.c
struct vb2_v4l2_buffer {
        struct vb2_buffer       vb2_buf;

        __u32                   flags;
        __u32                   field;
        struct timeval          timestamp;
        struct v4l2_timecode    timecode;
        __u32                   sequence;
};

Signed-off-by: Junghak Sung <jh1009.sung@samsung.com>
Signed-off-by: Geunyoung Kim <nenggun.kim@samsung.com>
Acked-by: Seung-Woo Kim <sw0312.kim@samsung.com>
Acked-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>