proc_fs.h: move struct mm_struct forward-declaration

Move the forward-declaration of struct mm_struct a little way up
proc_fs.h.  This fixes a bunch of "'struct mm_struct' declared inside
parameter list" warnings with CONFIG_PROC_FS=n

Signed-off-by: Ben Nizette <bn@niasdigital.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/proc_fs.h

@@ -9,6 +9,8 @@
 
 struct net;
 struct completion;
+struct mm_struct;
+
 /*
  * The proc filesystem constants/structures
  */
@@ -101,8 +103,6 @@ extern spinlock_t proc_subdir_lock;
 extern void proc_root_init(void);
 extern void proc_misc_init(void);
 
-struct mm_struct;
-
 void proc_flush_task(struct task_struct *task);
 struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *);
 int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir);