RDMA/core: Fix reported speed and width

When the returned speed from __ethtool_get_link_ksettings() is
SPEED_UNKNOWN this will lead to reporting a wrong speed and width for
providers that uses ib_get_eth_speed(), fix that by defaulting the
netdev_speed to SPEED_1000 in case the returned value from
__ethtool_get_link_ksettings() is SPEED_UNKNOWN.

Fixes: d4186194 ("IB/core: Add generic function to extract IB speed from netdev")
Link: https://lore.kernel.org/r/20200902124304.170912-1-kamalheib1@gmail.comSigned-off-by: Kamal Heib <kamalheib1@gmail.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/core/verbs.c

@@ -1801,7 +1801,7 @@ int ib_get_eth_speed(struct ib_device *dev, u8 port_num, u8 *speed, u8 *width)
 
 	dev_put(netdev);
 
-	if (!rc) {
+	if (!rc && lksettings.base.speed != (u32)SPEED_UNKNOWN) {
 		netdev_speed = lksettings.base.speed;
 	} else {
 		netdev_speed = SPEED_1000;