drm/radeon/mst: port some MST setup code from DAL.

This ports the DAL timeouts and MST rate calculations
for the hw from the DAL codebase.

Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/radeon: add DisplayPort MST support (v2)

This adds initial DP 1.2 MST support to radeon, on CAYMAN
and up in theory.

This is off by default.

v2: agd5f:
- add UNIPHY3 offsets
- move atom cmd table code into atombios_encoders.c
- whitespace cleanup
- replace some magic numbers with proper defines

Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/radeon: add some MST registers

These registers will be used later to setup

Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/radeon/kms: add ni_reg.h

This adds some new NI (northern islands) specific display
register defines.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>