hw/usb-msd: fix some usb requests

The usb-msd device emulation needs some small tweaks in the requests
emulations. For instance, the reset/maxlun requests are class/interface
specific so requests for them with the type class and recipient interface
bits sets have to be handled.

Signed-off-by: Arnaud Patard <arnaud.patard@rtp-net.org>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
diff --git a/hw/usb-msd.c b/hw/usb-msd.c
index e90a47e..e9235ea 100644
--- a/hw/usb-msd.c
+++ b/hw/usb-msd.c
@@ -321,17 +321,19 @@
         ret = 0;
         break;
     case EndpointOutRequest | USB_REQ_CLEAR_FEATURE:
-        if (value == 0 && index != 0x81) { /* clear ep halt */
-            goto fail;
-        }
+        ret = 0;
+        break;
+    case InterfaceOutRequest | USB_REQ_SET_INTERFACE:
         ret = 0;
         break;
         /* Class specific requests.  */
+    case (((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8) | MassStorageReset):
     case MassStorageReset:
         /* Reset state ready for the next CBW.  */
         s->mode = USB_MSDM_CBW;
         ret = 0;
         break;
+    case (((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8) | GetMaxLun):
     case GetMaxLun:
         data[0] = 0;
         ret = 1;