powerpc: Fix compile with icwsx support

Due to a collision between NO_CONTEXT->MMU_NO_CONTEXT change and
Anton's patch.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/mm/mmu_context_hash64.c b/arch/powerpc/mm/mmu_context_hash64.c
index c517815..3bafc3d 100644
--- a/arch/powerpc/mm/mmu_context_hash64.c
+++ b/arch/powerpc/mm/mmu_context_hash64.c
@@ -279,7 +279,7 @@
 	if (!mm->context.cop_lockp) {
 		__destroy_context(index);
 		subpage_prot_free(mm);
-		mm->context.id = NO_CONTEXT;
+		mm->context.id = MMU_NO_CONTEXT;
 		return -ENOMEM;
 	}
 	spin_lock_init(mm->context.cop_lockp);