mips_r4k: initialize i8259 after the ISA bus

Succeeding i8259 conversion to ISA requires this.
Signed-off-by: NAvi Kivity <avi@redhat.com>

hw/mips_r4k.c

@@ -256,8 +256,8 @@ void mips_r4k_init (ram_addr_t ram_size,
     cpu_mips_clock_init(env);
 
     /* The PIC is attached to the MIPS CPU INT0 pin */
-    i8259 = i8259_init(env->irq[2]);
     isa_bus_new(NULL, get_system_io());
+    i8259 = i8259_init(env->irq[2]);
     isa_bus_irqs(i8259);
 
     rtc_init(2000, NULL);