package/gst1-plugins-bad: add new va option

This option enables va plugin support.

These plugins are vaapi based encoders/decoders that are eventually
intended to replace the legacy vaapi plugins.

Details:
https://gstreamer.freedesktop.org/documentation/va/index.html



Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>