tg3: Fix single MSI-X vector coalescing

The interrupt coalescing setup code used the TG3_FLG2_USING_MSIX flag to
determine whether or not to configure the rx coalescing parameters.
This is incorrect for the single MSI-X vector case.  This patch changes
the code to look at the TG3_FLG3_ENABLE_RSS instead.
Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Reviewed-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/tg3.c

@@ -7447,7 +7447,7 @@ static void __tg3_set_coalesce(struct tg3 *tp, struct ethtool_coalesce *ec)
 		tw32(HOSTCC_TXCOAL_MAXF_INT, 0);
 	}
 
-	if (!(tp->tg3_flags2 & TG3_FLG2_USING_MSIX)) {
+	if (!(tp->tg3_flags3 & TG3_FLG3_ENABLE_RSS)) {
 		tw32(HOSTCC_RXCOL_TICKS, ec->rx_coalesce_usecs);
 		tw32(HOSTCC_RXMAX_FRAMES, ec->rx_max_coalesced_frames);
 		tw32(HOSTCC_RXCOAL_MAXF_INT, ec->rx_max_coalesced_frames_irq);