ext4: make various ext4 functions be static

These functions have no need to be exported beyond file context.

No functions needed to be moved for this commit; just some function
declarations changed to be static and removed from header files.

(A similar patch was submitted by Eric Sandeen, but I wanted to handle
code movement in separate patches to make sure code changes didn't
accidentally get dropped.)

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 94e6003..158d1bca 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -53,7 +53,7 @@
 #define CREATE_TRACE_POINTS
 #include <trace/events/ext4.h>
 
-struct proc_dir_entry *ext4_proc_root;
+static struct proc_dir_entry *ext4_proc_root;
 static struct kset *ext4_kset;
 struct ext4_lazy_init *ext4_li_info;
 struct mutex ext4_li_mtx;