Move shared pthread definitions to common headers

This patch removes all the replicated pthread definition accross the
architectures and consolidates it on shared headers.  The new
organization is as follow:

  * Architecture specific definition (such as pthread types sizes) are
    place in the new pthreadtypes-arch.h header in arch specific path.

  * All shared structure definition are moved to a common NPTL header
    at sysdeps/nptl/bits/pthreadtypes.h (with now includes the arch
    specific one for internal definitions).

  * Also, for C11 future thread support, both mutex and condition
    definition are placed in a common header at
    sysdeps/nptl/bits/thread-shared-types.h.

It is also a refactor patch without expected functional changes.
Checked with a build for all major ABI (aarch64-linux-gnu, alpha-linux-gnu,
arm-linux-gnueabi, i386-linux-gnu, ia64-linux-gnu,
m68k-linux-gnu, microblaze-linux-gnu, mips{64}-linux-gnu, nios2-linux-gnu,
powerpc{64le}-linux-gnu, s390{x}-linux-gnu, sparc{64}-linux-gnu,
tile{pro,gx}-linux-gnu, and x86_64-linux-gnu).

	* posix/Makefile (headers): Add pthreadtypes-arch.h and
	thread-shared-types.h.
	* sysdeps/aarch64/nptl/bits/pthreadtypes-arch.h: New file: arch
	specific thread definition.
	* sysdeps/alpha/nptl/bits/pthreadtypes-arch.h: Likewise.
	* sysdeps/arm/nptl/bits/pthreadtypes-arch.h: Likewise.
	* sysdeps/hppa/nptl/bits/pthreadtypes-arch.h: Likewise.
	* sysdeps/ia64/nptl/bits/pthreadtypes-arch.h: Likewise.
	* sysdeps/m68k/nptl/bits/pthreadtypes-arch.h: Likewise.
	* sysdeps/microblaze/nptl/bits/pthreadtypes-arch.h: Likewise.
	* sysdeps/mips/nptl/bits/pthreadtypes-arch.h: Likewise.
	* sysdeps/nios2/nptl/bits/pthreadtypes-arch.h: Likewise.
	* sysdeps/powerpc/nptl/bits/pthreadtypes-arch.h: Likewise.
	* sysdeps/s390/nptl/bits/pthreadtypes-arch.h: Likewise.
	* sysdeps/sh/nptl/bits/pthreadtypes-arch.h: Likewise.
	* sysdeps/sparc/nptl/bits/pthreadtypes-arch.h: Likewise.
	* sysdeps/tile/nptl/bits/pthreadtypes-arch.h: Likewise.
	* sysdeps/x86/nptl/bits/pthreadtypes-arch.h: Likewise.
	* sysdeps/nptl/bits/thread-shared-types.h: New file: shared
	thread definition between POSIX and C11.
	* sysdeps/aarch64/nptl/bits/pthreadtypes.h.: Remove file.
	* sysdeps/alpha/nptl/bits/pthreadtypes.h: Likewise.
	* sysdeps/arm/nptl/bits/pthreadtypes.h: Likewise.
	* sysdeps/hppa/nptl/bits/pthreadtypes.h: Likewise.
	* sysdeps/m68k/nptl/bits/pthreadtypes.h: Likewise.
	* sysdeps/microblaze/nptl/bits/pthreadtypes.h: Likewise.
	* sysdeps/mips/nptl/bits/pthreadtypes.h: Likewise.
	* sysdeps/nios2/nptl/bits/pthreadtypes.h: Likewise.
	* sysdeps/ia64/nptl/bits/pthreadtypes.h: Likewise.
	* sysdeps/powerpc/nptl/bits/pthreadtypes.h: Likewise.
	* sysdeps/s390/nptl/bits/pthreadtypes.h: Likewise.
	* sysdeps/sh/nptl/bits/pthreadtypes.h: Likewise.
	* sysdeps/sparc/nptl/bits/pthreadtypes.h: Likewise.
	* sysdeps/tile/nptl/bits/pthreadtypes.h: Likewise.
	* sysdeps/x86/nptl/bits/pthreadtypes.h: Likewise.
	* sysdeps/nptl/bits/pthreadtypes.h: New file: common thread
	definitions shared across all architectures.