drm/i915/huc: make "support huc" reflect HW capabilities

drm/i915/huc: make "support huc" reflect HW capabilities

We currently initialize HuC support based on GuC being enabled in
modparam; this means that huc_is_supported() can return false on HW that
does have a HuC when enable_guc=0. The rationale for this behavior is
that HuC requires GuC for authentication and therefore is not supported
by itself. However, we do not allow defining HuC fw wthout GuC fw and
selecting HuC in modparam implicitly selects GuC as well, so we can't
actually hit a scenario where HuC is selected alone. Therefore, we can
flip the support check to reflect the HW capabilities and fw
availability, which is more intuitive and will make it cleaner to log
HuC the difference between not supported in HW and not selected.

Removing the difference between GuC and HuC also allows us to simplify
the init_early, since we don't need to differentiate the support based
on the type of uC.

Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: John Harrison <John.C.Harrison@Intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20200326181121.16869-4-daniele.ceraolospurio@intel.com