mnt_init(): call shmem_init() unconditionally

No point having two call sites (earlier in init_rootfs() from
mnt_init() in case we are going to use shmem-style rootfs,
later from do_basic_setup() unconditionally), along with the
logics in shmem_init() itself to make the second call a no-op...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/init/do_mounts.c b/init/do_mounts.c
index e7f0b0f..864c032 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -643,14 +643,9 @@ struct file_system_type rootfs_fs_type = {
 	.kill_sb	= kill_litter_super,
 };
 
-int __init init_rootfs(void)
+void __init init_rootfs(void)
 {
-	int err = 0;
-
 	if (IS_ENABLED(CONFIG_TMPFS) && !saved_root_name[0] &&
-		(!root_fs_names || strstr(root_fs_names, "tmpfs"))) {
-		err = shmem_init();
+		(!root_fs_names || strstr(root_fs_names, "tmpfs")))
 		is_tmpfs = true;
-	}
-	return err;
 }