fs: Limit sys_mount to only request filesystem modules. (Part 3)

Somehow I failed to add the MODULE_ALIAS_FS for cifs, hostfs, hpfs,
squashfs, and udf despite what I thought were my careful checks :(

Add them now.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

fs/hostfs/hostfs_kern.c

@@ -993,6 +993,7 @@ static struct file_system_type hostfs_type = {
 	.kill_sb	= hostfs_kill_sb,
 	.fs_flags 	= 0,
 };
+MODULE_ALIAS_FS("hostfs");
 
 static int __init init_hostfs(void)
 {