drm/amdgpu: Drop redundant parameter in amdgpu_gfx_kiq_init_ring

Drop redundant parameters in function amdgpu_gfx_kiq_init_ring
to simplify the code

Signed-off-by: Ma Jun <Jun.Ma2@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>