drm/i915/display: Ignore IGNORE_PSR2_HW_TRACKING for platforms without sel fetch

For platforms without selective fetch this register is reserved so
do not write 0 to it.

Cc: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201007195238.53955-1-jose.souza@intel.com