powerpc: Stop using non-architected shared_proc field in lppaca

Although the shared_proc field in the lppaca works today, it is
not architected. A shared processor partition will always have a non
zero yield_count so use that instead. Create a wrapper so users
don't have to know about the details.

In order for older kernels to continue to work on KVM we need
to set the shared_proc bit. While here, remove the ugly bitfield.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/include/asm/spinlock.h b/arch/powerpc/include/asm/spinlock.h
index 5b23f91..7c345b6 100644
--- a/arch/powerpc/include/asm/spinlock.h
+++ b/arch/powerpc/include/asm/spinlock.h
@@ -96,7 +96,7 @@
 
 #if defined(CONFIG_PPC_SPLPAR)
 /* We only yield to the hypervisor if we are in shared processor mode */
-#define SHARED_PROCESSOR (local_paca->lppaca_ptr->shared_proc)
+#define SHARED_PROCESSOR (lppaca_shared_proc(local_paca->lppaca_ptr))
 extern void __spin_yield(arch_spinlock_t *lock);
 extern void __rw_yield(arch_rwlock_t *lock);
 #else /* SPLPAR */