Revert "Revert "drm/amdkfd: Make TLB flush conditional on mapping""

This reverts commit 7ed9876c

.

Revert reason: The issue has been resolved.

Signed-off-by: Eric Huang <jinhuieric.huang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>