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>

init/initramfs.c

@@ -12,6 +12,7 @@
 #include <linux/file.h>
 #include <linux/memblock.h>
 #include <linux/namei.h>
+#include <linux/init_syscalls.h>
 
 static ssize_t __init xwrite(struct file *file, const char *p, size_t count,
 		loff_t *pos)
@@ -301,7 +302,7 @@ static void __init clean_path(char *path, umode_t fmode)
 		if (S_ISDIR(st.mode))
 			ksys_rmdir(path);
 		else
-			ksys_unlink(path);
+			init_unlink(path);
 	}
 }