drm/amdgpu/gfx11: add support for disable_kq

Plumb in support for disabling kernel queues in
GFX11.  We have to bring up a GFX queue briefly in
order to initialize the clear state.  After that
we can disable it.

v2: use ring counts per Felix' suggestion
v3: fix stream fault handler, enable EOP interrupts
v4: fix MEC interrupt offset (Sunil)

Reviewed-by: Sunil Khatri <sunil.khatri@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>