drm/i915: Nuke drm_crtc_state and use intel_atomic_state instead

This is one of the patches to start replacing drm pointers
and use the intel_atomic_state and intel_crtc to derive
the necessary intel state variables required for the intel
modeset functions.

v3:
* Remove the unwanted newline (Ville)
v2:
* Flip the function arguments (Ville)
* Remove some remaining instances of drm pointers (Ville)
* Use old_crtc_state and new_crtc_state (Ville)

Suggested-by: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Reviewed-by: Ville Syrjala <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190415182210.13347-1-manasi.d.navare@intel.com