drm/amdkfd/gfx10: Calling amdgpu functions to invalidate TLB

Calling amdgpu function to invalidate TLB, instead of using a
kfd implementation. Delete the kfd local TLB invalidation
implementation.

Signed-off-by: Oak Zeng <Oak.Zeng@amd.com>
Reviewed-by: Christian Konig <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>