drm/amdgpu: Potential uninitialized variable in amdgpu_vm_update_directories()

commit 78aa02c7 upstream.

After commit ea09729c ("drm/amdgpu: rework page directory filling
v2") then it becomes a lot harder to verify that "r" is initialized.  My
static checker complains and so I've reviewed the code.  It does look
like it might be buggy... Anyway, it doesn't hurt to set "r" to zero
at the start.
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

@@ -744,7 +744,7 @@ static int amdgpu_vm_update_pd_or_shadow(struct amdgpu_device *adev,
 int amdgpu_vm_update_page_directory(struct amdgpu_device *adev,
                                    struct amdgpu_vm *vm)
 {
-	int r;
+	int r = 0;
 
 	r = amdgpu_vm_update_pd_or_shadow(adev, vm, true);
 	if (r)