drm/amdkfd: Swap trap temporary registers in gfx10 trap handler

ttmp[4:5] hold information useful to the debugger. Use ttmp[14:15]
instead, aligning implementation with gfx9 trap handler.

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