locking/mcs: Allow architecture specific asm files to be used for contended case

This patch allows each architecture to add its specific assembly optimized
arch_mcs_spin_lock_contended and arch_mcs_spinlock_uncontended for
MCS lock and unlock functions.

Signed-off-by: Tim Chen <[email protected]>
Cc: Scott J Norton <[email protected]>
Cc: Raghavendra K T <[email protected]>
Cc: AswinChandramouleeswaran <[email protected]>
Cc: George Spelvin <[email protected]>
Cc: Rik vanRiel <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: MichelLespinasse <[email protected]>
Cc: Peter Hurley <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Alex Shi <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Tim Chen <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: "Figo.zhang" <[email protected]>
Cc: "Paul E.McKenney" <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Cc: Waiman Long <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Matthew R Wilcox <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/1390347382.3138.67.camel@schen9-DESK
Signed-off-by: Ingo Molnar <[email protected]>

arch/cris/include/asm/Kbuild

@@ -9,6 +9,7 @@ generic-y += exec.h
 generic-y += hash.h
 generic-y += kvm_para.h
 generic-y += linkage.h
+generic-y += mcs_spinlock.h
 generic-y += module.h
 generic-y += preempt.h
 generic-y += trace_clock.h