drm/amdgpu: add parameter to disable kernel queues

On chips that support user queues, setting this option
will disable kernel queues to be used to validate
user queues without kernel queues.

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