drm/i915: s/pipe_config/crtc_state/ in pfit functions

Follow the new naming convention and call the crtc state
"crtc_state", and while at it drop the redundant crtc argument.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200422161917.17389-4-ville.syrjala@linux.intel.com
Reviewed-by: Manasi Navare <manasi.d.navare@intel.com>