esp (sparc32) Extra scsi data.

> ESP: Message Accepted (12)
> ESP: Transfer status (sense=0)
> ESP: read reg[5]: 0x20
> ESP: read reg[4]: 0x07
> ESP: read reg[7]: 0x02
> Extra scsi data. Fatal error.

It looks like "Message Accepted" shouldn't write a response. At least
ESP_RFLAGS must definetely be 0. With the following fix OBP goes one
step further:
Signed-off-by: NArtyom Tarasenko <atar4qemu@gmail.com>
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>

hw/esp.c

@@ -528,9 +528,10 @@ static void esp_mem_writeb(void *opaque, target_phys_addr_t addr, uint32_t val)
             break;
         case CMD_MSGACC:
             DPRINTF("Message Accepted (%2.2x)\n", val);
-            write_response(s);
             s->rregs[ESP_RINTR] = INTR_DC;
             s->rregs[ESP_RSEQ] = 0;
+            s->rregs[ESP_RFLAGS] = 0;
+            esp_raise_irq(s);
             break;
         case CMD_PAD:
             DPRINTF("Transfer padding (%2.2x)\n", val);