ftgmac100: Fix interrupt status "Packet transmitted on ethernet"

The second field of the TX descriptor has a set of flags to choose
when the transmit interrupt is raised : after the packet has been sent
on the ethernet or after it has been moved into the TX FIFO. But we
don't model that today.

Simply raise the "Packet transmitted on ethernet" interrupt status bit
as soon as the packet is sent by QEMU.

Cc: Frederic Konrad <konrad.frederic@yahoo.fr>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Message-Id: <20200819100956.2216690-11-clg@kaod.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>

hw/net/ftgmac100.c

@@ -547,9 +547,7 @@ static void ftgmac100_do_tx(FTGMAC100State *s, uint32_t tx_ring,
             qemu_send_packet(qemu_get_queue(s->nic), s->frame, frame_size);
             ptr = s->frame;
             frame_size = 0;
-            if (flags & FTGMAC100_TXDES1_TXIC) {
-                s->isr |= FTGMAC100_INT_XPKT_ETH;
-            }
+            s->isr |= FTGMAC100_INT_XPKT_ETH;
         }
 
         if (flags & FTGMAC100_TXDES1_TX2FIC) {