drm/i915/icp: Add the ID for ICL PCH - ICP

Add the PCI ID for the ICL PCH - ICP.

v2: rebased.
v3: rebased.
v4: fix ICP name.
v5: fix the ID mask (Fei Li).
v6 (from Paulo): bikesheds.

Cc: Li, Fei <fei.li@intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Anusha Srivatsa <anusha.srivatsa@intel.com>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180111180010.24357-9-paulo.r.zanoni@intel.com