ext4: rename {exit,init}_ext4_*() to ext4_{exit,init}_*()

This is a cleanup to avoid namespace leaks out of fs/ext4

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index e3bcc06..381ac56 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2705,7 +2705,7 @@
 
 #endif
 
-int __init init_ext4_mballoc(void)
+int __init ext4_init_mballoc(void)
 {
 	ext4_pspace_cachep = KMEM_CACHE(ext4_prealloc_space,
 					SLAB_RECLAIM_ACCOUNT);
@@ -2730,7 +2730,7 @@
 	return 0;
 }
 
-void exit_ext4_mballoc(void)
+void ext4_exit_mballoc(void)
 {
 	int i;
 	/*