drm/i915/gvt: Make gvt_vgpu_err use pr_err

gvt_vgpu_err means something goes wrong. We need the error propagates to
kernel message by default.

Signed-off-by: Changbin Du <changbin.du@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
1 file changed