Consolidate pwrite/pwrite64 implementations

This patch consolidates all the pwrite/pwrite64 implementation for Linux
in only one (sysdeps/unix/sysv/linux/pwrite{64}.c).  It also removes the
syscall from the auto-generation using assembly macros.

For pwrite{64} offset argument placement the new SYSCALL_LL{64} macro
is used.  For pwrite ports that do not define __NR_pwrite will use
__NR_pwrite64 and for pwrite64 ports that dot define __NR_pwrite64 will
use __NR_pwrite for the syscall.

Checked on x86_64, x32, i386, aarch64, and ppc64le.

	* sysdeps/unix/sysv/linux/arm/pwrite.c: Remove file.
	* sysdeps/unix/sysv/linux/arm/pwrite64.c: Likewise.
	* sysdeps/unix/sysv/linux/generic/wordsize-32/pwrite.c: Likewise.
	* sysdeps/unix/sysv/linux/generic/wordsize-32/pwrite64.c: Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/pwrite.c: Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/pwrite64.c: Likewise.
	* sysdeps/unix/sysv/linux/wordsize-64/pwrite64.c: Likewise.
	* sysdeps/unix/sysv/linux/wordsize-64/syscalls.list (prite): Remove
	syscalls generation.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/sysdep.h
	[__NR_pwrite64] (__NR_write): Remove define.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/sysdep.h
	[__NR_pwrite64] (__NR_write): Remove define.
	* sysdeps/unix/sysv/linux/pwrite.c [__NR_pwrite64] (__NR_pwrite):
	Remove define.
	(__libc_pwrite): Use SYSCALL_LL macro on offset argument.
	* sysdeps/unix/sysv/linux/pwrite64.c [__NR_pwrite64] (__NR_pwrite):
	Remove define.
	(__libc_pwrite64): Use SYSCALL_LL64 macro on offset argument.
	* sysdeps/unix/sysv/linux/sh/pwrite.c: Rewrite using default
	Linux implementation as base.
	* sysdeps/unix/sysv/linux/sh/pwrite64.c: Likewise.
	* sysdeps/unix/sysv/linux/mips/pwrite.c: Likewise.
	* sysdeps/unix/sysv/linux/mips/pwrite64.c: Likewise.