Consolidate sparc clone, fork, and vfork implementations.

Consolidate sparc clone, fork, and vfork implementations.

	* nptl/sysdeps/unix/sysv/linux/sparc/sparc32/clone.S: Delete.
	* nptl/sysdeps/unix/sysv/linux/sparc/sparc32/pt-vfork.S: Delete.
	* nptl/sysdeps/unix/sysv/linux/sparc/sparc32/vfork.S: Moved ...
	* sysdeps/unix/sysv/linux/sparc/sparc32/vfork.S: ... here.
	* nptl/sysdeps/unix/sysv/linux/sparc/sparc64/clone.S: Delete.
	* nptl/sysdeps/unix/sysv/linux/sparc/sparc64/pt-vfork.S: Delete.
	* nptl/sysdeps/unix/sysv/linux/sparc/sparc64/vfork.S: Moved ...
	* sysdeps/unix/sysv/linux/sparc/sparc64/vfork.S: ... here.
	* sysdeps/unix/sysv/linux/sparc/fork.S: Delete.
	* sysdeps/unix/sysv/linux/sparc/pt-vfork.S: New file.
	* sysdeps/unix/sysv/linux/sparc/sparc32/clone.S (__thread_start):
	Remove RESET_PID cpp guards.
	* sysdeps/unix/sysv/linux/sparc/sparc64/clone.S (__thread_start):
	Remove RESET_PID cpp guards.
	* sysdeps/unix/sysv/linux/sparc/vfork.S: Delete.