amd64: initialize IPI scoreboard earlier

The initializer just needs working malloc(9) and two constants that
are set at hammer_time().

Fixes:	648fa3558c

Reviewed by:		avg, markj
Differential Revision:	https://reviews.freebsd.org/D58714

sys/amd64/amd64/mp_machdep.c

@@ -598,7 +598,7 @@ invl_scoreboard_init(void *arg __unused)
 		invl_op_pg = INVL_OP_PG;
 	}
 }
-SYSINIT(invl_ops, SI_SUB_SMP - 1, SI_ORDER_ANY, invl_scoreboard_init, NULL);
+SYSINIT(invl_ops, SI_SUB_KMEM, SI_ORDER_ANY, invl_scoreboard_init, NULL);
 
 static uint32_t *
 invl_scoreboard_getcpu(u_int cpu)