ext4: fix spelling errors and a comment in extent_status tree

Replace "assertation" with "assertion" in lots and lots of debugging
messages.

Correct the comment stating when ext4_es_insert_extent() is used.  It
was no doubt tree at one point, but it is no longer true...

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Zheng Liu <gnehzuil.liu@gmail.com>
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 19a1643..98b9bff 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -465,7 +465,7 @@
 	if (es_map->m_lblk != map->m_lblk ||
 	    es_map->m_flags != map->m_flags ||
 	    es_map->m_pblk != map->m_pblk) {
-		printk("ES cache assertation failed for inode: %lu "
+		printk("ES cache assertion failed for inode: %lu "
 		       "es_cached ex [%d/%d/%llu/%x] != "
 		       "found ex [%d/%d/%llu/%x] retval %d flags %x\n",
 		       inode->i_ino, es_map->m_lblk, es_map->m_len,
@@ -558,7 +558,7 @@
 
 #ifdef ES_AGGRESSIVE_TEST
 		if (retval != map->m_len) {
-			printk("ES len assertation failed for inode: %lu "
+			printk("ES len assertion failed for inode: %lu "
 			       "retval %d != map->m_len %d "
 			       "in %s (lookup)\n", inode->i_ino, retval,
 			       map->m_len, __func__);
@@ -659,7 +659,7 @@
 
 #ifdef ES_AGGRESSIVE_TEST
 		if (retval != map->m_len) {
-			printk("ES len assertation failed for inode: %lu "
+			printk("ES len assertion failed for inode: %lu "
 			       "retval %d != map->m_len %d "
 			       "in %s (allocation)\n", inode->i_ino, retval,
 			       map->m_len, __func__);
@@ -1642,7 +1642,7 @@
 
 #ifdef ES_AGGRESSIVE_TEST
 		if (retval != map->m_len) {
-			printk("ES len assertation failed for inode: %lu "
+			printk("ES len assertion failed for inode: %lu "
 			       "retval %d != map->m_len %d "
 			       "in %s (lookup)\n", inode->i_ino, retval,
 			       map->m_len, __func__);