libofa: fix patch application
Without the change patches fail to apply as `$patches` contain compressed
tarball:
applying patch /nix/store/yrl3bq4ag3787yq32zawxnd6nsyk4a8r-libofa_0.9.3-5.debian.tar.gz
(Stripping trailing CRs from patch; use --binary to disable.)
patching file lib/signal_op.cpp
(Stripping trailing CRs from patch; use --binary to disable.)
patching file examples/example.cpp
(Stripping trailing CRs from patch; use --binary to disable.)
With `patch-2.8` it will become an error.