Generic semaphore implementation

Semaphores are no longer performance-critical, so a generic C
implementation is better for maintainability, debuggability and
extensibility.  Thanks to Peter Zijlstra for fixing the lockdep
warning.  Thanks to Harvey Harrison for pointing out that the
unlikely() was unnecessary.

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index 00d44c6..6235f72 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -7,7 +7,7 @@
 # Object file lists.
 
 obj-y		:= compat.o entry-armv.o entry-common.o irq.o \
-		   process.o ptrace.o semaphore.o setup.o signal.o \
+		   process.o ptrace.o setup.o signal.o \
 		   sys_arm.o stacktrace.o time.o traps.o
 
 obj-$(CONFIG_ISA_DMA_API)	+= dma.o