drm/i915/gvt: free VFIO region space in vgpu detach

VFIO region space is allocated when one region is registered for
one vgpu. So free the space when destroy the vgpu.

Also change the parameter of detach_vgpu callback to use vgpu directly.

Fixes: b851adeac0 ("drm/i915/gvt: Add opregion support")
Reviewed-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Hang Yuan <hang.yuan@linux.intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

drivers/gpu/drm/i915/gvt/hypercall.h

@@ -41,7 +41,7 @@ struct intel_gvt_mpt {
 	int (*host_init)(struct device *dev, void *gvt, const void *ops);
 	void (*host_exit)(struct device *dev, void *gvt);
 	int (*attach_vgpu)(void *vgpu, unsigned long *handle);
-	void (*detach_vgpu)(unsigned long handle);
+	void (*detach_vgpu)(void *vgpu);
 	int (*inject_msi)(unsigned long handle, u32 addr, u16 data);
 	unsigned long (*from_virt_to_mfn)(void *p);
 	int (*enable_page_track)(unsigned long handle, u64 gfn);