drm/i915/pxp: Implement funcs to create the TEE channel

Implement the funcs to create the TEE channel, so kernel can
send the TEE commands directly to TEE for creating the arbitrary
(default) session.

v2: fix locking, don't pollute dev_priv (Chris)

v3: wait for mei PXP component to be bound.

v4: drop the wait, as the component might be bound after i915 load
completes. We'll instead check when sending a tee message.

v5: fix an issue with mei_pxp module removal

v6: don't use fetch_and_zero in fini (Rodrigo)

Signed-off-by: Huang, Sean Z <sean.z.huang@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210924191452.1539378-6-alan.previn.teres.alexis@intel.com