drm/nv50/disp: fix selection of bios script for analog outputs

Analog output number was overwritten by value from digital output path.
Fix it.

Fixes resume from s2ram: https://bugs.freedesktop.org/show_bug.cgi?id=58729
(as stumbled on by J Binder, Pontus Fuchs and me)
Fixes blank screen on module load (reported by Sune Mølgaard).

Fixes regression from commit 186ecad2


("drm/nv50/disp: move remaining interrupt handling into core").

Reported-by: J Binder <wheel@herr-der-mails.de>
Reported-by: Pontus Fuchs <pontus.fuchs@gmail.com>
Reported-by: Sune Mølgaard <sune@molgaard.org>
Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Tested-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Tested-by: Sune Mølgaard <sune@molgaard.org>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>