tg3: Add New 5719 Read DMA workaround

commit 091f0ea30074bc43f9250961b3247af713024bc6 upstream.

After Power-on-reset, the 5719's TX DMA length registers may contain
uninitialized values and cause TX DMA to stall.  Check for invalid
values and set a register bit to flush the TX channels.  The bit
needs to be turned off after the DMA channels have been flushed.

Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --cc drivers/net/ethernet/broadcom/tg3.c
Simple merge

diff --cc drivers/net/ethernet/broadcom/tg3.h
Simple merge