drm/amdkfd: CWSR with software scheduler

This patch adds support to program trap handler settings
when loading driver with software scheduler (sched_policy=2).

Signed-off-by: Mukul Joshi <mukul.joshi@amd.com>
Suggested-by: Jay Cornwall <Jay.Cornwall@amd.com>
Reviewed-by: Harish Kasiviswanathan <Harish.Kasiviswanathan@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>