net: hibmcge: disable Relaxed Ordering to fix RX packet corruption

net: hibmcge: disable Relaxed Ordering to fix RX packet corruption

When SMMU is disabled, the hibmcge driver may receive corrupted packets.
The hardware writes packet data and descriptors to the same page, but
with Relaxed Ordering enabled, PCI write transactions may not be
strictly ordered. This can cause the driver to observe a valid
descriptor before the corresponding packet data is fully written.

Fix this by clearing PCI_EXP_DEVCTL_RELAX_EN in the PCI bridge control
register to ensure strict write ordering between packet data and
descriptors.

Fixes: f72e25594061 ("net: hibmcge: Implement rx_poll function to receive packets")
Signed-off-by: Jijie Shao <shaojijie@huawei.com>
Link: https://patch.msgid.link/20260525144525.94884-2-shaojijie@huawei.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>