drm/i915/gvt: fix a typo: "registeration" -> "registration".

Fix a typo in the error message reporting.

Signed-off-by: Peng Hao <peng.hao2@zte.com.cn>
Signed-off-by: Zhi Wang <zhi.a.wang@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>