drm/i915/icl: Add missing device ID

We are missing PCI device ID for SKU ICLLP U GT 1.5F (0x8A54) as per BSPec.

BSpec: 19092

Signed-off-by: Mika Kahola <mika.kahola@intel.com>
Reviewed-by: Clint Taylor <Clinton.A.Taylor@intel.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190617082413.22549-1-mika.kahola@intel.com