drm/amdkfd: Handle restart of kfd_ioctl_wait_events

When kfd_ioctl_wait_events needs to restart due to a signal, we need to
update the timeout to account for the time already elapsed. We also need
to undo auto_reset of events that have signaled already, so that the
restarted ioctl will be able to count those signals again.

This fixes infinite hangs when kfd_ioctl_wait_events is interrupted by a
signal.

Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-and-tested-by: Xiaogang Chen <Xiaogang.Chen@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>