drm/i915: Rename PIPECONF refresh select bits

Rename the PIPECONF refresh rate select bits to be
less cryptic. Also nothing eDP specific about these as they
also select between FP0 vs. FP1 for the DPLL and thus can be
used to change the refresh rate on other output types as well.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220310004802.16310-9-ville.syrjala@linux.intel.com


Reviewed-by: Jani Nikula <jani.nikula@intel.com>