This reverts commit 36bf9321.

It causes SVM regressions on Vega10 with XNACK-ON. Just revert it
at the moment.

./kfdtest --gtest_filter=KFDSVMRangeTest.MigratePolicyTest
Signed-off-by: Lang Yu <Lang.Yu@amd.com>
Reviewed-by: Philip Yang<Philip.Yang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>