posix: Consolidate Linux mq_timedreceive syscall

posix: Consolidate Linux mq_timedreceive syscall

This patch consolidates the mq_timedreceive Linux syscall generation
on sysdeps/unix/sysv/linux/mq_timedreceive.c.  It basically removes it
from architecture auto-generation list.

Checked on i686-linux-gnu, x86_64-linux-gnu, x86_64-linux-gnux32,
arch64-linux-gnu, arm-linux-gnueabihf, powerpc64le-linux-gnu,
sparc64-linux-gnu, and sparcv9-linux-gnu.

	* rt/Makefile (CFLAGS-mq_timedreceive.c): New flag.
	* sysdeps/unix/sysv/linux/mq_timedreceive.c: New file.
	* sysdeps/unix/sysv/linux/syscalls.list (mq_timedreceive): Remove
	from auto-generation list.