net: thunderbolt: Enable end-to-end flow control also in transmit

net: thunderbolt: Enable end-to-end flow control also in transmit

[ Upstream commit a8065af3346ebd7c76ebc113451fb3ba94cf7769 ]

According to USB4 specification, if E2E flow control is disabled for
the Transmit Descriptor Ring, the Host Interface Adapter Layer shall
not require any credits to be available before transmitting a Tunneled
Packet from this Transmit Descriptor Ring, so e2e flow control should
be enabled in both directions.

Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Link: https://lore.kernel.org/20250624153805.GC2824380@black.fi.intel.com
Signed-off-by: zhangjianrong <zhangjianrong5@huawei.com>
Link: https://patch.msgid.link/20250628093813.647005-1-zhangjianrong5@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>