drm/xe/uc: Change assertion to error on huc authentication failure

drm/xe/uc: Change assertion to error on huc authentication failure

The fault injection test can cause the xe_huc_auth function to fail.
This is an intentional failure, so in this scenario we don't want to
throw an assert and taint the kernel, because that will impact CI
execution.

Signed-off-by: Zhanjun Dong <zhanjun.dong@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Link: https://patch.msgid.link/20251027214212.2856903-1-zhanjun.dong@intel.com