i915/display/dmc: Add Support for PipeC and PipeD DMC

So far we had support for main, PipeA and PipeB
DMC. If we find a binary from PipeA-D, lets load it.

Cc: Imre Deak <imre.deak@intel.com>
Signed-off-by: Anusha Srivatsa <anusha.srivatsa@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211006204547.669464-1-anusha.srivatsa@intel.com