reiserfs: typo comment fix

Fix trivial typo in code comment (change adn for and), also change comment
style for proper coding style.
Signed-off-by: Davidlohr Bueso <dave@gnu.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

include/linux/reiserfs_fs.h

@@ -360,7 +360,7 @@ int is_reiserfs_jr(struct reiserfs_super_block *rs);
 /* the spot for the super in versions 3.5 - 3.5.10 (inclusive) */
 #define REISERFS_OLD_DISK_OFFSET_IN_BYTES (8 * 1024)
 
-// reiserfs internal error code (used by search_by_key adn fix_nodes))
+/* reiserfs internal error code (used by search_by_key and fix_nodes)) */
 #define CARRY_ON      0
 #define REPEAT_SEARCH -1
 #define IO_ERROR      -2