[media] doc-rst: Document ioctl LIRC_GET_FEATURES

The documentation for this ioctl was really crappy.

Add a better documentation, using the lirc.4 man pages as a
reference, plus what was written originally at the lirc-ioctl.

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