drm/amdkfd: update GFX11 CWSR trap handler

drm/amdkfd: update GFX11 CWSR trap handler

With corresponding FW change fixes issue where triggering CWSR on a
workgroup with waves in s_barrier wouldn't lead to a back-off and
therefore cause a hang.

Signed-off-by: Jay Cornwall <jay.cornwall@amd.com>
Tested-by: Graham Sider <Graham.Sider@amd.com>
Acked-by: Harish Kasiviswanathan <Harish.Kasiviswanathan@amd.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Graham Sider <Graham.Sider@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>