drm/nouveau/disp: add internal representaion of output paths and connectors

This will, at some point, be used to replace various bits and pieces of
code doing direct bios parsing.  For now, it'll just be used for some
DP improvements.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

diff --cc drivers/gpu/drm/nouveau/Makefile
Simple merge

diff --cc drivers/gpu/drm/nouveau/core/engine/disp/base.c
Simple merge

diff --cc drivers/gpu/drm/nouveau/core/engine/disp/conn.c
Simple merge

diff --cc drivers/gpu/drm/nouveau/core/engine/disp/conn.h
Simple merge

diff --cc drivers/gpu/drm/nouveau/core/engine/disp/nv50.h
Simple merge

diff --cc drivers/gpu/drm/nouveau/core/engine/disp/outp.c
Simple merge

diff --cc drivers/gpu/drm/nouveau/core/engine/disp/outp.h
Simple merge

diff --cc drivers/gpu/drm/nouveau/core/engine/disp/piornv50.c
Simple merge

diff --cc drivers/gpu/drm/nouveau/core/engine/disp/priv.h
Simple merge

diff --cc drivers/gpu/drm/nouveau/core/include/engine/disp.h
Simple merge