drm/xe/rtp: Save OA nonpriv registers to register save/restore lists

drm/xe/rtp: Save OA nonpriv registers to register save/restore lists

Now we can save OA whitelisting nonpriv registers to register save/restore
lists. OA nonpriv registers are saved to both hwe->oa_sr as well as
hwe->reg_sr.

During probe, resume and gt-reset flows KMD will apply hwe->reg_sr,
ensuring OA registers are de-whitelisted after these events. For
engine-reset, hwe->reg_sr is registered with GuC and GuC will apply these
registers, ensuring OA registers are de-whitelisted after engine resets.

hwe->oa_sr is used for whitelisting or de-whitelisting OA registers during
OA operation, by toggling the 'deny' bit on oa stream open/close.

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/20260615224227.34880-6-ashutosh.dixit@intel.com
(cherry picked from commit 3a3c3e56db2923daaf1a5353cd6463a4cdaf4ffa)
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>