dma-buf: revert "return only unsignaled fences in dma_fence_unwrap_for_each v3"

This reverts commit 8f619737.

It turned out that this is not correct. Especially the sync_file info
IOCTL needs to see even signaled fences to correctly report back their
status to userspace.

Instead add the filter in the merge function again where it makes sense.

Signed-off-by: Christian König <christian.koenig@amd.com>
Tested-by: Karolina Drobnik <karolina.drobnik@intel.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220712102849.1562-1-christian.koenig@amd.com