drm/amdkfd: add reset cause in gpu pre-reset smi event

reset cause is requested by customer as additional
info for gpu reset smi event.

v2: integerate reset sources suggested by Lijo Lazar

Signed-off-by: Eric Huang <jinhuieric.huang@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>