drm/xe/hdcp: Fix condition for hdcp gsc cs requirement

Add condition for check of hdcp gsc cs requirement rather than
assuming gsc cs to always be required when xe is loaded. It is not
required for display version < 14

--v2
-Use display version in commit message [Lucas]

Fixes: 152f2df9 ("drm/xe/hdcp: Enable HDCP for XE")
Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Uma Shankar <uma.shankar@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240308154939.1940960-2-suraj.kandpal@intel.com