drm/i915/huc: better define HuC status getparam possible return values.

The current HuC status getparam return values are a bit confusing in
regards to what happens in some scenarios. In particular, most of the
error cases cause the ioctl to return an error, but a couple of them,
INIT_FAIL and LOAD_FAIL, are not explicitly handled and neither is
their expected return value documented; these 2 error cases therefore
end up into the catch-all umbrella of the "HuC not loaded" case, with
this case therefore including both some error scenarios and the load
in progress one.

The updates included in this patch change the handling so that all
error cases behave the same way, i.e. return an errno code, and so
that the HuC load in progress case is unambiguous.

The patch also includes a small change to the FW init path to make sure
we always transition to an error state if something goes wrong.

Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Tony Ye <tony.ye@intel.com>
Acked-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Acked-by: Tony Ye <tony.ye@intel.com>
Reviewed-by: Alan Previn <alan.previn.teres.alexis@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220928004145.745803-14-daniele.ceraolospurio@intel.com