drm/i915/uc: Drop explicit gt param in some uc_fw functions

There is no need to pass explicit gt since we already have
a trick to get parent gt from uc_fw, we only need to use it.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
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/20191211124549.59516-3-michal.wajdeczko@intel.com