Starting with Linux kernel commit v5.6-rc1~93^2~102, the definition
of struct v4l2_buffer provided by the kernel depends on the flavour
of struct timeval provided by libc.  This effectively means that we
cannot use the definition provided by the kernel, neither in the decoder
nor in tests.

* kernel_v4l2_types.h: New file.
* Makefile.am (libstrace_a_SOURCES): Add it.
* types/v4l2.h (struct_v4l2_buffer): Remove.
* v4l2.c: Include "kernel_v4l2_types.h".
Replace struct_v4l2_buffer with kernel_v4l2_buffer_t.
(VIDIOC_QUERYBUF, VIDIOC_QBUF, VIDIOC_DQBUF, VIDIOC_PREPARE_BUF):
Redefine.
(print_v4l2_buffer): Use print_timeval64_data_size to print timestamp
field.
* linux/32/ioctls_inc_align16.h (VIDIOC_QUERYBUF, VIDIOC_QBUF,
VIDIOC_DQBUF, VIDIOC_PREPARE_BUF): Update.
* linux/32/ioctls_inc_align32.h: Likewise.
* linux/32/ioctls_inc_align64.h: Likewise.
* xlat/v4l2_ioctl_cmds.in (VIDIOC_QUERYBUF, VIDIOC_QBUF,
VIDIOC_DQBUF, VIDIOC_PREPARE_BUF): Comment out.
* tests/ioctl_v4l2.c: Include "kernel_v4l2_types.h".
(main): Replace struct_v4l2_buffer with kernel_v4l2_buffer_t.
(VIDIOC_QUERYBUF, VIDIOC_QBUF, VIDIOC_DQBUF, VIDIOC_PREPARE_BUF):
Redefine.
* tests/ioctl_v4l2-success.c: Likewise.

Resolves: https://github.com/strace/strace/issues/133