Remove unused sys_pread64 and sys_pwrite64 parsers on Linux

* io.c [HAVE_LONG_LONG_OFF_T]: Remove sys_pread64 and sys_pwrite64
aliases.
(sys_pread64, sys_pwrite64): Define these functions only on
[SVR4 && _LFS64_LARGEFILE] platform.
* linux/mips/syscallent.h: Use sys_pread and sys_pwrite to handle
appropriate syscalls.
* linux/syscall.h (sys_pread64, sys_pwrite64): Remove.
* syscall.c (dumpio): Check sys_pread64 and sys_pwrite64 only on
[SVR4 && _LFS64_LARGEFILE] platform.
4 files changed