drm/amdgpu: split gfx_v9_0_kiq_init_queue into two

One for KIQ and one for the KCQ. This simplifies the logic and
allows for future optimizations.

Acked-by: Tom St Denis <tom.stdenis@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>