drm/amdkfd: Add Sienna_Cichlid trap handler support

- Replace SQC stores with TCP stores
- Synchronize with MSG_SAVEWAVE via lgkmcnt
- HW_REG_IB_STS is now read-only

Signed-off-by: Jay Cornwall <jay.cornwall@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>