drm/i915/display/dp: Do not enable PSR if VRR is enabled

Even though our HW supports PSR + VRR, the available panels
do not work reliably with PSR and VRR together. So if user
requested VRR and is supported by HW enable that and do not
enable PSR in that case.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Reviewed-by: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210122232647.22688-7-manasi.d.navare@intel.com