drm/i915/pxp: Invalidate all PXP fw sessions during teardown

A gap was recently discovered where if an application did not
invalidate all of the stream keys (intentionally or not), and the
driver did a full PXP global teardown on the GT subsystem, we
find that future session creation would fail on the security
firmware's side of the equation. i915 is the entity that needs
ensure the sessions' state across both iGT and security firmware
are at a known clean point when performing a full global teardown.

Architecturally speaking, i915 should inspect all active sessions
and submit the invalidate-stream-key PXP command to the security
firmware for each of them. However, for the upstream i915 driver
we only support the arbitration session that can be created
so that will be the only session we will cleanup.

Signed-off-by: Alan Previn <alan.previn.teres.alexis@intel.com>
Reviewed-by: Juston Li <justonli@chromium.org>
Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230125082637.118970-5-alan.previn.teres.alexis@intel.com