nptl: Add adapt_count parameter to lll_unlock_elision

Adding this parameter will give architectures more freedom in
how they choose to update this variable.  This change has no
effect on architectures which choose not to use it.

	* nptl/pthread_mutex_unlock.c(lll_unlock_elision):
	Add elision adapt_count parameter to list of arguments.
	* sysdeps/unix/sysv/linux/powerpc/lowlevellock.h
	(lll_unlock_elision): Update with new parameter list
	* sysdeps/unix/sysv/linux/s390/lowlevellock.h
	(lll_unlock_elision): Likewise
	* sysdeps/unix/sysv/linux/x86_64/lowlevellock.h
	(lll_unlock_elision): Likewise