drm/i915/aml: Add new Amber Lake PCI ID

This new AML PCI ID uses the same gen graphics as Coffe Lake not a
Kaby Lake one like the other AMLs.

So to make it more explicit renaming INTEL_AML_GT2_IDS to
INTEL_AML_KBL_GT2_IDS and naming this id as INTEL_AML_CFL_GT2_IDS.

v2:
- missed add new AML macro to INTEL_CFL_IDS()
- added derivated platform initials to AML macros

Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180927010650.22731-1-jose.souza@intel.com