optionrom: disallow int19 redirect for pnp roms.

optionrom: disallow int19 redirect for pnp roms.

Check whenever pnp roms attempt to redirect int19, and in case it does
log a message and undo the redirect.

A pnp rom should not need this, we have BEVs and BCVs for that.
Nevertheless there are roms in the wild which are redirecting int19.
At least some BIOS implementations for physical hardware have a config
option in the setup to allow/disallow int19 redirections, so just not
allowing this seems to be the way to deal with this situation.

Buglink: https://bugzilla.redhat.com//show_bug.cgi?id=1642135
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Tested-by: Matt DeVillier <matt.devillier@gmail.com>