sh: Kill off unused flush_icache_user_range().

We use flush_cache_page() outright in copy_to_user_page(), and nothing
else needs it, so just kill it off. SH-5 still defines its own version,
but that too will go away in the same fashion once it converts over.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/mm/cache-sh4.c

@@ -401,20 +401,6 @@ void flush_cache_range(struct vm_area_struct *vma, unsigned long start,
 	}
 }
 
-/*
- * flush_icache_user_range
- * @vma: VMA of the process
- * @page: page
- * @addr: U0 address
- * @len: length of the range (< page size)
- */
-void flush_icache_user_range(struct vm_area_struct *vma,
-			     struct page *page, unsigned long addr, int len)
-{
-	flush_cache_page(vma, addr, page_to_pfn(page));
-	mb();
-}
-
 /**
  * __flush_cache_4096
  *