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-sh5.c

@@ -655,7 +655,7 @@ void flush_icache_range(unsigned long start, unsigned long end)
  * range following a poke into the program text through the ptrace() call
  * from another process (e.g. for BRK instruction insertion).
  */
-void flush_icache_user_range(struct vm_area_struct *vma,
+static void flush_icache_user_range(struct vm_area_struct *vma,
 			struct page *page, unsigned long addr, int len)
 {