wangxunx: select CONFIG_PHYLINK where needed

wangxunx: select CONFIG_PHYLINK where needed

The ngbe driver needs phylink:

arm-linux-gnueabi-ld: drivers/net/ethernet/wangxun/libwx/wx_ethtool.o: in function `wx_nway_reset':
wx_ethtool.c:(.text+0x458): undefined reference to `phylink_ethtool_nway_reset'
arm-linux-gnueabi-ld: drivers/net/ethernet/wangxun/ngbe/ngbe_main.o: in function `ngbe_remove':
ngbe_main.c:(.text+0x7c): undefined reference to `phylink_destroy'
arm-linux-gnueabi-ld: drivers/net/ethernet/wangxun/ngbe/ngbe_main.o: in function `ngbe_open':
ngbe_main.c:(.text+0xf90): undefined reference to `phylink_connect_phy'
arm-linux-gnueabi-ld: drivers/net/ethernet/wangxun/ngbe/ngbe_mdio.o: in function `ngbe_mdio_init':
ngbe_mdio.c:(.text+0x314): undefined reference to `phylink_create'

Add the missing Kconfig description for this.

Fixes: bc2426d74aa3 ("net: ngbe: convert phylib to phylink")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20240111162828.68564-1-arnd@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>