drm/i915/pps: Rename intel_pps_delay members

drm/i915/pps: Rename intel_pps_delay members

Stop using the semi-random eDP spec T1,T3,... names for the
power sequencing delays, and instead call them by their human
readable names. Much easier to keep track what delay goes
where when you don't have to constantly cross reference against
the eDP spec.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241106215859.25446-4-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>