BugLink: https://bugs.launchpad.net/bugs/1864774

[ Upstream commit 3f4b7e6a ]

Make sure the SONIC's DMA engine is idle before altering the transmit
and receive descriptors. Add a helper for this as it will be needed
again.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>