drm/amdgpu: use the same HDP flush registers for all nbio 7.4.x

drm/amdgpu: use the same HDP flush registers for all nbio 7.4.x

[ Upstream commit 912db6a58738e8be502838eb6a88f207ba356cd7 ]

Align aldebaran with all other asics.  One HDP bit per
SDMA instance, aligned with firmware.  This is effectively
a revert of
commit a0f9f8546668 ("drm/amdgpu/nbio7.4: don't use GPU_HDP_FLUSH bit 12").
On further discussions with the relevant hardware teams,
re-align the bits for SDMA.

Fixes: a0f9f8546668 ("drm/amdgpu/nbio7.4: don't use GPU_HDP_FLUSH bit 12")
Reviewed-by: Kent Russell <kent.russell@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>