drm/xe/rtp: Keep track of non-OA nonpriv slots

drm/xe/rtp: Keep track of non-OA nonpriv slots

In order to dynamically whitelist/dewhitelist OA registers on OA stream
open/close, we need to keep track of nonpriv slots occupied by non-OA
register whitelists.

Fixes: 828a8eaf37c3 ("drm/xe/oa: Add MMIO trigger support")
Cc: stable@vger.kernel.org # v6.12+
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Reviewed-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Link: https://patch.msgid.link/20260615224227.34880-4-ashutosh.dixit@intel.com