drm/amdgpu: fix incorrect vm flags to map bo

It should use vm flags instead of pte flags
to specify bo vm attributes.

Fixes: 7946340f ("drm/amdgpu: Move csa related code to separate file")
Signed-off-by: Jack Xiao <Jack.Xiao@amd.com>
Reviewed-by: Likun Gao <Likun.Gao@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit b08425fa)