There is no point in selecting HuC firmware if GuC is unsupported
or it was already disabled, as we need GuC to authenticate HuC.

While around, make uc_fw_init_early work without direct access
to whole i915, pass only needed platform/rev info.
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190807170034.8440-3-michal.wajdeczko@intel.com