openrisc: add ioremap_nocache declaration before include asm-generic/io.h and sync ioremap prototype with it.

A future commit for the nds32 architecture bootstrap("asm-generic/io.h: move
ioremap_nocache/ioremap_uc/ioremap_wc/ioremap_wt out of ifndef CONFIG_MMU")
will move the ioremap_nocache out of the CONFIG_MMU ifdef. This means that
in order to suppress re-definition errors we need to setup #define's before
importing asm-generic/io.h.

Also, the change adds a prototype for ioremap where size is size_t so fix that
as well.

Signed-off-by: Greentime Hu <greentime@andestech.com>
Acked-by: Stafford Horne <shorne@gmail.com>

arch/openrisc/include/asm/io.h

@@ -29,13 +29,14 @@
 #define PIO_OFFSET		0
 #define PIO_MASK		0
 
+#define ioremap_nocache ioremap_nocache
 #include <asm-generic/io.h>
 #include <asm/pgtable.h>
 
 extern void __iomem *__ioremap(phys_addr_t offset, unsigned long size,
 				pgprot_t prot);
 
-static inline void __iomem *ioremap(phys_addr_t offset, unsigned long size)
+static inline void __iomem *ioremap(phys_addr_t offset, size_t size)
 {
 	return __ioremap(offset, size, PAGE_KERNEL);
 }