ext4: fix ext4_show_options for file systems w/o journal

Instead of removing EXT4_MOUNT_JOURNAL_CHECKSUM from s_def_mount_opt as
I assume was intended, all other options were blown away leading to
_ext4_show_options() output being incorrect.

Fixes: 1e381f6 ("ext4: do not allow journal_opts for fs w/o journal")
Signed-off-by: Debabrata Banerjee <dbanerje@akamai.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: stable@kernel.org

fs/ext4/super.c

@@ -4349,7 +4349,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 				 "data=, fs mounted w/o journal");
 			goto failed_mount_wq;
 		}
-		sbi->s_def_mount_opt &= EXT4_MOUNT_JOURNAL_CHECKSUM;
+		sbi->s_def_mount_opt &= ~EXT4_MOUNT_JOURNAL_CHECKSUM;
 		clear_opt(sb, JOURNAL_CHECKSUM);
 		clear_opt(sb, DATA_FLAGS);
 		sbi->s_journal = NULL;