kill mm argument of vm_munmap()

it's always current->mm

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 86a692c..74aa71b 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1403,7 +1403,7 @@
 
 /* These take the mm semaphore themselves */
 extern unsigned long vm_brk(unsigned long, unsigned long);
-extern int vm_munmap(struct mm_struct *, unsigned long, size_t);
+extern int vm_munmap(unsigned long, size_t);
 extern unsigned long vm_mmap(struct file *, unsigned long,
         unsigned long, unsigned long,
         unsigned long, unsigned long);