drm/i915/dp: Rename some variables in xelpd_dsc_compute_link_config()

drm/i915/dp: Rename some variables in xelpd_dsc_compute_link_config()

Use the _x16 suffix for all .4 fixed point variables. Drop compressed_
prefix, as it's implied from the precision suffix.

As dsc_min_bpp and dsc_max_bpp change domain from int to .4 in the
middle of the function, they remain the same for now.

Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/91dd6ef53683b624a978101cca7322ea3e5e2f7b.1738327620.git.jani.nikula@intel.com