Define more subsystem orders.

Intended for use with module_init_order() in the LinuxKPI.

MFC after:	1 week
Sponsored by:	Mellanox Technologies

sys/sys/kernel.h

@@ -183,6 +183,10 @@ enum sysinit_elem_order {
 	SI_ORDER_SECOND		= 0x0000001,	/* second*/
 	SI_ORDER_THIRD		= 0x0000002,	/* third*/
 	SI_ORDER_FOURTH		= 0x0000003,	/* fourth*/
+	SI_ORDER_FIFTH		= 0x0000004,	/* fifth*/
+	SI_ORDER_SIXTH		= 0x0000005,	/* sixth*/
+	SI_ORDER_SEVENTH	= 0x0000006,	/* seventh*/
+	SI_ORDER_EIGHTH		= 0x0000007,	/* eighth*/
 	SI_ORDER_MIDDLE		= 0x1000000,	/* somewhere in the middle */
 	SI_ORDER_ANY		= 0xfffffff	/* last*/
 };