drm/i915/display/adlp: Remove code related to underrun recovery

This is not supported for ADLP and is not needed.

Signed-off-by: Swathi Dhanavanthri <swathi.dhanavanthri@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220302231119.16876-1-swathi.dhanavanthri@intel.com