drm/i915/kbl: Add WaSkipStolenMemoryFirstPage for A0

We need this for kbl a0 boards. Note that this should be also
for bxt A0 but we omit that on purpose as bxt A0's are
out of fashion already.

References: HSD#1912158, HSD#4393097
Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1465309159-30531-5-git-send-email-mika.kuoppala@intel.com