virito-pci: fix OVERRUN problem

Overrunning array "proxy->guest_features" of 2 4-byte
elements at element index 2 (byte offset 8) using index
"proxy->gfselect" (which evaluates to 2). Normally, the
Linux kernel driver just read/write '0' or '1' as the
"proxy->gfselect" values, so using '<' instead of '=<' to
make coverity happy and avoid potential harm.

Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: NGonglei <arei.gonglei@huawei.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

hw/virtio/virtio-pci.c

@@ -977,7 +977,7 @@ static uint64_t virtio_pci_common_read(void *opaque, hwaddr addr,
         val = proxy->gfselect;
         break;
     case VIRTIO_PCI_COMMON_GF:
-        if (proxy->gfselect <= ARRAY_SIZE(proxy->guest_features)) {
+        if (proxy->gfselect < ARRAY_SIZE(proxy->guest_features)) {
             val = proxy->guest_features[proxy->gfselect];
         }
         break;
@@ -1052,7 +1052,7 @@ static void virtio_pci_common_write(void *opaque, hwaddr addr,
         proxy->gfselect = val;
         break;
     case VIRTIO_PCI_COMMON_GF:
-        if (proxy->gfselect <= ARRAY_SIZE(proxy->guest_features)) {
+        if (proxy->gfselect < ARRAY_SIZE(proxy->guest_features)) {
             proxy->guest_features[proxy->gfselect] = val;
             virtio_set_features(vdev,
                                 (((uint64_t)proxy->guest_features[1]) << 32) |