drm/amdkfd: Remove duplicate functions update_mqd_hiq()

The functions are the same as update_mqd().

Signed-off-by: Yong Zhao <Yong.Zhao@amd.com>
Reviewed-by: Zhan Liu <zhan.liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>