consolidate io_remap_pfn_range definitions

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

arch/openrisc/include/asm/pgtable.h

@@ -446,9 +446,6 @@ static inline void update_mmu_cache(struct vm_area_struct *vma,
 
 #define kern_addr_valid(addr)           (1)
 
-#define io_remap_pfn_range(vma, vaddr, pfn, size, prot)         \
-	remap_pfn_range(vma, vaddr, pfn, size, prot)
-
 #include <asm-generic/pgtable.h>
 
 /*