Revert "drm/amdkfd: Add heavy-weight TLB flush after unmapping"

This reverts commit 1098d658.

Reason for revert: it causes regressions on several Asics.
Signed-off-by: Eric Huang <jinhuieric.huang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdkfd/kfd_chardev.c

@@ -1563,7 +1563,6 @@ static int kfd_ioctl_unmap_memory_from_gpu(struct file *filep,
 			       i, args->n_devices);
 			goto unmap_memory_from_gpu_failed;
 		}
-		kfd_flush_tlb(peer_pdd, TLB_FLUSH_HEAVYWEIGHT);
 		args->n_success = i+1;
 	}
 	kfree(devices_arr);