drm/amdgpu: Use the right function for hdp flush

[ Upstream commit c235a713 ]

There are a few prechecks made before HDP flush like a flush is not
required on APU bare metal. Using hdp callback directly bypasses those
checks. Use amdgpu_device_flush_hdp which takes care of prechecks.

Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 1d9bff4c)
Signed-off-by: Sasha Levin <sashal@kernel.org>