drm/xe/oa: Allow reading after disabling OA stream

drm/xe/oa: Allow reading after disabling OA stream

commit 9be6fd9fbd2032b683e51374497768af9aaa228a upstream.

Some OA data might be present in the OA buffer when OA stream is
disabled. Allow UMD's to retrieve this data, so that all data till the
point when OA stream is disabled can be retrieved.

v2: Update tail pointer after disable (Umesh)

Fixes: efb315d0a013 ("drm/xe/oa/uapi: Read file_operation")
Cc: stable@vger.kernel.org
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Reviewed-by: Umesh Nerlige Ramappa<umesh.nerlige.ramappa@intel.com>
Link: https://patch.msgid.link/20260313053630.3176100-1-ashutosh.dixit@intel.com
(cherry picked from commit 4ff57c5e8dbba23b5457be12f9709d5c016da16e)
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>