tg3: Assign correct tx margin for 5719

Commit d309a46e42542223946d3a9e4e239fdc945cb53e, entitled
"tg3: 5719: Prevent tx data corruption", was supposed to contain the tx
margin adjustment but it looks like it somehow was omitted.  This patch
fixes the problem.

Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Reviewed-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/tg3.c b/drivers/net/tg3.c
index ca6b3cb..4dc0756 100644
--- a/drivers/net/tg3.c
+++ b/drivers/net/tg3.c
@@ -8206,6 +8206,10 @@
 	    GET_ASIC_REV(tp->pci_chip_rev_id) == ASIC_REV_57780 ||
 	    (tp->tg3_flags3 & TG3_FLG3_5717_PLUS)) {
 		val = tr32(TG3_RDMA_RSRVCTRL_REG);
+		if (GET_ASIC_REV(tp->pci_chip_rev_id) == ASIC_REV_5719) {
+			val &= ~TG3_RDMA_RSRVCTRL_TXMRGN_MASK;
+			val |= TG3_RDMA_RSRVCTRL_TXMRGN_320B;
+		}
 		tw32(TG3_RDMA_RSRVCTRL_REG,
 		     val | TG3_RDMA_RSRVCTRL_FIFO_OFLW_FIX);
 	}