dump.f2fs: macOS does not support lsetxattr

Fixes: a66d49fd2678 ("dump.f2fs: Dump symlinks as symlinks")
Signed-off-by: Łukasz Patron <priv.luk@gmail.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>