net: eth: altera: Resolve false errors from MSGDMA to TSE

This patch resolves false errors from MSGDMA in TX mSGDMA MM to ST
mode, and is a continuation of the patch recently submitted by Andrea
Oetken. The MSGDMA had a logic bug that masked detection of this issue
prior to Quartus 14.1/Build 164. When the MSGDMA logic bug was addressed
in Quartus 14.1/Build 164, the driver problem was exposed.

The problem is corrected by making sure MSGDMA_DESC_CTL_TR_ERR_IRQ is not
set for any of the transmit DMA descriptors, and only used for receive
descriptors.

Fixes: 71cd26e7 altera tse: Error-Bit on tx-avalon-stream always set.

Signed-off-by: Chee Nouk Phoon <cnphoon@altera.com>
Signed-off-by: Vince Bridgers <vbridger@opensource.altera.com&gt;a>
Cc: Andreas Oetken <ennoerlangen@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>