mm: remove blackfin MPU support

The CONFIG_MPU option was only defined on blackfin, and that architecture
is now being removed, so the respective code can be simplified.

A lot of other microcontrollers have an MPU, but I suspect that if we
want to bring that support back, we'd do it differently anyway.

Signed-off-by: Arnd Bergmann <[e-mail]>

kernel/module.c

···
 	/* Finally, free the core (containing the module structure) */
 	disable_ro_nx(&mod->core_layout);
 	module_memfree(mod->core_layout.base);
-
-#ifdef CONFIG_MPU
-	update_protections(current->mm);
-#endif
 }
 
 void *__symbol_get(const char *symbol)

mm/nommu.c

···
 }
 
 /*
- * update protection on a vma
- */
-static void protect_vma(struct vm_area_struct *vma, unsigned long flags)
-{
-#ifdef CONFIG_MPU
-	struct mm_struct *mm = vma->vm_mm;
-	long start = vma->vm_start & PAGE_MASK;
-	while (start < vma->vm_end) {
-		protect_page(mm, start, flags);
-		start += PAGE_SIZE;
-	}
-	update_protections(mm);
-#endif
-}
-
-/*
  * add a VMA into a process's mm_struct in the appropriate place in the list
  * and tree and add to the address space's page tree also if not an anonymous
  * page
···
 
 	mm->map_count++;
 	vma->vm_mm = mm;
-
-	protect_vma(vma, vma->vm_flags);
 
 	/* add the VMA to the mapping */
 	if (vma->vm_file) {
···
 	struct address_space *mapping;
 	struct mm_struct *mm = vma->vm_mm;
 	struct task_struct *curr = current;
-
-	protect_vma(vma, 0);
 
 	mm->map_count--;
 	for (i = 0; i < VMACACHE_SIZE; i++) {