Consolidate non cancellable pause call

This patch consolidates all the non cancellable pause calls to use
the __pause_nocancel identifier.  For non cancellable targets it will
be just a macro to call the default respective symbol while on Linux
will be a internal one.

Checked on x86_64-linux-gnu, x86_64-linux-gnu-x32, and i686-linux-gnu.

	* nptl/pthread_mutex_lock.c (__pthread_mutex_lock_full): Replace
	pause_not_cancel with __pause_nocancel.
	* sysdeps/generic/not-cancel.h (pause_not_cancel): Remove macro.
	(__pause_nocancel): New macro.
	* sysdeps/unix/sysv/linux/not-cancel.h (pause_not_cancel): Remove
	macro.
	(__pause_nocancel): New prototype.
	* sysdeps/unix/sysv/linux/pause.c (__pause_nocancel): New function.