drm/i915/firmware: Update to DMC v2.12 on TGL

Add support to the latest DMC firmware.

Cc: Madhunitha Pradeep <madhumitha.tolakanahalli.pradeep@intel.com>
Signed-off-by: Anusha Srivatsa <anusha.srivatsa@intel.com>
Reviewed-by: Madhumitha Pradeep <madhumitha.tolakanahalli.pradeep@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210721215238.24980-3-anusha.srivatsa@intel.com