drm/i915: Clean up various display chicken registers

Modernize a bunch of display chicken registers by using
REG_BIT() & co.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230411191429.29895-3-ville.syrjala@linux.intel.com


Reviewed-by: Jouni Högander <jouni.hogander@intel.com>