drm/i915/mtl: Create separate reg file for PICA registers

Create a separate file to store registers for PICA chips
C10 and C20.

v2: Rename file (Jani)
v3: Use _PICK_EVEN_2RANGES() macro (Lucas)
    Coding style fixed (Lucas)
v4: Redefine macros (Imre)

Reviewed-by: Vinod Govindapillai <vinod.govindapillai@intel.com>
Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Signed-off-by: Mika Kahola <mika.kahola@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230413212443.1504245-3-radhakrishna.sripada@intel.com