init: add an init_unlink helper

Add a simple helper to unlink with a kernel space file name and switch
the early init code over to it.  Remove the now unused ksys_unlink.

Signed-off-by: Christoph Hellwig <hch@lst.de>
diff --git a/init/do_mounts.h b/init/do_mounts.h
index 20e7fec..104d843 100644
--- a/init/do_mounts.h
+++ b/init/do_mounts.h
@@ -16,7 +16,7 @@ extern int root_mountflags;
 
 static inline __init int create_dev(char *name, dev_t dev)
 {
-	ksys_unlink(name);
+	init_unlink(name);
 	return ksys_mknod(name, S_IFBLK|0600, new_encode_dev(dev));
 }