xenbus: Remove duplicate inclusion of linux/init.h

This patch remove duplicate inclusion of linux/init.h in
xenbus_dev_frontend.c.
Confirm successfully compile after remove the line.

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Reviewed-by: Juergen Gross <jgross@suse.com>

drivers/xen/xenbus/xenbus_dev_frontend.c

@@ -55,7 +55,6 @@
 #include <linux/string.h>
 #include <linux/slab.h>
 #include <linux/miscdevice.h>
-#include <linux/init.h>
 
 #include <xen/xenbus.h>
 #include <xen/xen.h>