drm/i915: Convert most of atomic commit to take more intel state

drm/i915: Convert most of atomic commit to take more intel state

Instead of passing along drm_crtc_state and drm_atomic_state, pass
along more intel_atomic_state and intel_crtc_state. This will
make the code more readable by not casting between drm state
and intel state all the time.

While at it, rename old_state to state, with the get_new/old helpers
there is no point in distinguishing between state before and after
swapping state any more. (Ville)

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190628085517.31886-3-maarten.lankhorst@linux.intel.com