drm/i915: Use after free in error path in intel_vgpu_create_workload()

We can't free "workload" until after the printk or it's a use after
free.

Fixes: 2089a76a

 ("drm/i915/gvt: Checking workload's gma earlier")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>