m68knommu: remove empty __iounmap() it is no used

The empty __iounmap() function is not used on m68knommu at all.
Signed-off-by: Greg Ungerer <gerg@uclinux.org>

arch/m68k/include/asm/io_no.h

@@ -145,7 +145,6 @@ static inline void io_insl(unsigned int addr, void *buf, int len)
 #define IOMAP_WRITETHROUGH		3
 
 extern void *__ioremap(unsigned long physaddr, unsigned long size, int cacheflag);
-extern void __iounmap(void *addr, unsigned long size);
 
 static inline void *ioremap(unsigned long physaddr, unsigned long size)
 {

arch/m68knommu/mm/kmap.c

@@ -35,15 +35,6 @@ void iounmap(void *addr)
 {
 }
 
-/*
- * __iounmap unmaps nearly everything, so be careful
- * it doesn't free currently pointer/page tables anymore but it
- * wans't used anyway and might be added later.
- */
-void __iounmap(void *addr, unsigned long size)
-{
-}
-
 /*
  * Set new cache mode for some kernel address space.
  * The caller must push data for that range itself, if such data may already