drm/i915: Sort the mess around ICP TC hotplugs regs

Move the DSC stuff out from the middle of the ICP HPD register
definitions. The location seems to have been selected by a
dice roll.

SHPD_FILTER_CNT addition also went astray due to the DSC
mess, so we also fix that vs. ICP_TC_HPD_{SHORT,LONG}_DETECT().
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201006143349.5561-2-ville.syrjala@linux.intel.comReviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>