ext4: correct comment for ext4_ext_check_cache

The comment for ext4_ext_check_cache has a litte mistake.

Signed-off-by: Robin Dong <[e-mail]>
Signed-off-by: "Theodore Ts'o" <[e-mail]>

fs/ext4/extents.c

···
 }
 
 /*
- * ext4_ext_in_cache()
+ * ext4_ext_check_cache()
  * Checks to see if the given block is in the cache.
  * If it is, the cached extent is stored in the given
  * cache extent pointer.  If the cached extent is a hole,