sh: Fix up NUMA build for 29-bit.

pmb_bolt_mapping() is undefined on 29-bit builds, so provide a stub.
This fixes up the NUMA build on platforms lacking PMB support.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/sh/include/asm/mmu.h b/arch/sh/include/asm/mmu.h
index 19fe845..56e4418 100644
--- a/arch/sh/include/asm/mmu.h
+++ b/arch/sh/include/asm/mmu.h
@@ -66,6 +66,13 @@
 
 #else
 
+static inline int
+pmb_bolt_mapping(unsigned long virt, phys_addr_t phys,
+		 unsigned long size, pgprot_t prot)
+{
+	return -EINVAL;
+}
+
 static inline void __iomem *
 pmb_remap_caller(phys_addr_t phys, unsigned long size,
 		 pgprot_t prot, void *caller)