proc: rearrange args

Rearrange args for smaller code.

lookup revolves around memcmp() which gets len 3rd arg, so propagate
length as 3rd arg.

readdir and lookup add additional arg to VFS ->readdir and ->lookup, so
better add it to the end.

Space savings on x86_64:

	add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-18 (-18)
	Function                                     old     new   delta
	proc_readdir                                  22      13      -9
	proc_lookup                                   18       9      -9

proc_match() is smaller if not inlined, I promise!

Link: http://lkml.kernel.org/r/20180104175958.GB5204@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index 5ba3178..d697c8a 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -153,10 +153,9 @@ extern bool proc_fill_cache(struct file *, struct dir_context *, const char *, i
  * generic.c
  */
 extern struct dentry *proc_lookup(struct inode *, struct dentry *, unsigned int);
-extern struct dentry *proc_lookup_de(struct proc_dir_entry *, struct inode *,
-				     struct dentry *);
+struct dentry *proc_lookup_de(struct inode *, struct dentry *, struct proc_dir_entry *);
 extern int proc_readdir(struct file *, struct dir_context *);
-extern int proc_readdir_de(struct proc_dir_entry *, struct file *, struct dir_context *);
+int proc_readdir_de(struct file *, struct dir_context *, struct proc_dir_entry *);
 
 static inline struct proc_dir_entry *pde_get(struct proc_dir_entry *pde)
 {