drm/i915/dp: implement get_hw_state

Also add some macros to make the pipe computation a bit easier.

v2: I've mixed up the CPT and !CPT PORT_TO_PIPE macro variants ...

Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2 files changed