drm/amdgpu:make ctx_add_fence interruptible(v2)

otherwise a gpu hang will make application couldn't be killed
under timedout=0 mode

v2:
Fix memoryleak job/job->s_fence issue
unlock mn
remove the ERROR msg after waiting being interrupted

Signed-off-by: Monk Liu <Monk.Liu@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>