drm/i915: coffeelake supports hdcp2.2

This includes other platforms that utilize the same gen graphics as
CFL: AML, WHL and CML.

Signed-off-by: Juston Li <juston.li@intel.com>
Reviewed-by: Ramalingam C <ramalingam.c@intel.com>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191011181918.29618-1-juston.li@intel.com