[media] vidioc-querycap.rst: Better format tables on PDF output

Both tables on this rst file were not shown right, as they miss
the proper tag (tabularcolumns) to specify the column widths
required for PDF and LaTeX output.

Also, the second table is too big to fit into one page. So,
it should use the longtable class to allow it to be split into
two pages.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>