net: hibmcge: Implement some ethtool_ops functions

Implement the .get_drvinfo .get_link .get_link_ksettings to get
the basic information and working status of the driver.
Implement the .set_link_ksettings to modify the rate, duplex,
and auto-negotiation status.

Signed-off-by: Jijie Shao <shaojijie@huawei.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>