* nds32/Makefile.in: Alter filename.
* nds32/syscall_argv.S: Rename to _argv.S
* nds32/syscall_argvlen.S: Rename to _argvlen.S
* nds32/syscall_chdir.S: Rename to _chdir.S
* nds32/syscall_chmod.S: Rename to _chmod.S
* nds32/syscall_close.S: Rename to _close.S
* nds32/syscall_exit.S: Rename to _exit.S
* nds32/syscall_fstat.S: Rename to _fstat.S
* nds32/syscall_getpid.S: Rename to _getpid.S
* nds32/syscall_gettimeofday.S: Rename to _gettimeofday.S
* nds32/syscall_isatty.S: Rename to _isatty.S
* nds32/syscall_kill.S: Rename to _kill.S
* nds32/syscall_link.S: Rename to _link.S
* nds32/syscall_lseek.S: Rename to _lseek.S
* nds32/syscall_open.S: Rename to _open.S
* nds32/syscall_read.S: Rename to _read.S
* nds32/syscall_rename.S: Rename to _rename.S
* nds32/syscall_sbrk.S: Rename to _sbrk.S
* nds32/syscall_stat.S: Rename to _stat.S
* nds32/syscall_system.S: Rename to _system.S
* nds32/syscall_time.S: Rename to _time.S
* nds32/syscall_times.S: Rename to _times.S
* nds32/syscall_unlink.S: Rename to _unlink.S
* nds32/syscall_utime.S: Rename to _utime.S
* nds32/syscall_write.S: Rename to _write.S
