Ensure to reset the tx_timer_active flag in xgbe_stop(),
otherwise a port restart may result in tx timeout due to
uncleared flag.

Fixes: c635eaac ("amd-xgbe: Remove Tx coalescing")
Co-developed-by: NSudheesh Mavila <sudheesh.mavila@amd.com>
Signed-off-by: NSudheesh Mavila <sudheesh.mavila@amd.com>
Signed-off-by: NRaju Rangoju <Raju.Rangoju@amd.com>
Acked-by: NTom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20220127060222.453371-1-Raju.Rangoju@amd.comSigned-off-by: NJakub Kicinski <kuba@kernel.org>