sh: fixed PMB mode refactoring.

This introduces some much overdue chainsawing of the fixed PMB support.
fixed PMB was introduced initially to work around the fact that dynamic
PMB mode was relatively broken, though they were never intended to
converge. The main areas where there are differences are whether the
system is booted in 29-bit mode or 32-bit mode, and whether legacy
mappings are to be preserved. Any system booting in true 32-bit mode will
not care about legacy mappings, so these are roughly decoupled.

Regardless of the entry point, PMB and 32BIT are directly related as far
as the kernel is concerned, so we also switch back to having one select
the other.

With legacy mappings iterated through and applied in the initialization
path it's now possible to finally merge the two implementations and
permit dynamic remapping overtop of remaining entries regardless of
whether boot mappings are crafted by hand or inherited from the boot
loader.

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 c7426ad..4b0882b 100644
--- a/arch/sh/include/asm/mmu.h
+++ b/arch/sh/include/asm/mmu.h
@@ -65,11 +65,29 @@
 	struct pmb_entry *link;
 };
 
+#ifdef CONFIG_PMB
 /* arch/sh/mm/pmb.c */
 long pmb_remap(unsigned long virt, unsigned long phys,
 	       unsigned long size, unsigned long flags);
 void pmb_unmap(unsigned long addr);
 int pmb_init(void);
+#else
+static inline long pmb_remap(unsigned long virt, unsigned long phys,
+			     unsigned long size, unsigned long flags)
+{
+	return -EINVAL
+}
+
+static inline void pmb_unmap(unsigned long addr)
+{
+}
+
+static inline int pmb_init(void)
+{
+	return -ENODEV;
+}
+#endif /* CONFIG_PMB */
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* __MMU_H */