Fix files_linux.go to work on 386
Fix files_linux.go to work on 386

Because Timeval has an int32 field on 386, use syscall.NsecToTimeval to build the Timeval in a cross-arch way.

keybase/go-fuse,cmars/tools,cmars/tools,cmars/tools,keybase/go-fuse,cmars/tools,keybase/go-fuse