drm/i915/scaler: s/intel_crtc/crtc/ etc.

Rename some variables from the intel_foo to just foo, to match
the more modern style used throughout the driver.

Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241107122658.21901-2-ville.syrjala@linux.intel.com