drm/amdgpu: avoid reading vf2pf info size from FB

[ Upstream commit 3bcc0ee14768d886cedff65da72d83d375a31a56 ]

VF can't access FB when host is doing mode1 reset. Using sizeof to get
vf2pf info size, instead of reading it from vf2pf header stored in FB.

Signed-off-by: Zhigang Luo <Zhigang.Luo@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c

@@ -586,7 +586,7 @@ static int amdgpu_virt_write_vf2pf_data(struct amdgpu_device *adev)
 
 	vf2pf_info->checksum =
 		amd_sriov_msg_checksum(
-		vf2pf_info, vf2pf_info->header.size, 0, 0);
+		vf2pf_info, sizeof(*vf2pf_info), 0, 0);
 
 	return 0;
 }