net: stmmac: xgmac: Disable Flow Control when 1 or more queues are in AV

net: stmmac: xgmac: Disable Flow Control when 1 or more queues are in AV

BugLink: https://bugs.launchpad.net/bugs/1855306
[ Upstream commit 132f2f20c9866325d12c155aca06d260f358d3cb ]

When in AVB mode we need to disable flow control to prevent MAC from
pausing in TX side.

Fixes: ec6ea8e3eee9 ("net: stmmac: Add CBS support in XGMAC2")
Signed-off-by: Jose Abreu <Jose.Abreu@synopsys.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Connor Kuehl <connor.kuehl@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>