This driver uses functions that are supplied by the Kconfig symbol
PHYLIB, so select it to ensure that they are built as needed.

When CONFIG_ADIN1110=y and CONFIG_PHYLIB=m, there are multiple build
(linker) errors that are resolved by this Kconfig change:

   ld: drivers/net/ethernet/adi/adin1110.o: in function `adin1110_net_open':
   drivers/net/ethernet/adi/adin1110.c:933: undefined reference to `phy_start'
   ld: drivers/net/ethernet/adi/adin1110.o: in function `adin1110_probe_netdevs':
   drivers/net/ethernet/adi/adin1110.c:1603: undefined reference to `get_phy_device'
   ld: drivers/net/ethernet/adi/adin1110.c:1609: undefined reference to `phy_connect'
   ld: drivers/net/ethernet/adi/adin1110.o: in function `adin1110_disconnect_phy':
   drivers/net/ethernet/adi/adin1110.c:1226: undefined reference to `phy_disconnect'
   ld: drivers/net/ethernet/adi/adin1110.o: in function `devm_mdiobus_alloc':
   include/linux/phy.h:455: undefined reference to `devm_mdiobus_alloc_size'
   ld: drivers/net/ethernet/adi/adin1110.o: in function `adin1110_register_mdiobus':
   drivers/net/ethernet/adi/adin1110.c:529: undefined reference to `__devm_mdiobus_register'
   ld: drivers/net/ethernet/adi/adin1110.o: in function `adin1110_net_stop':
   drivers/net/ethernet/adi/adin1110.c:958: undefined reference to `phy_stop'
   ld: drivers/net/ethernet/adi/adin1110.o: in function `adin1110_disconnect_phy':
   drivers/net/ethernet/adi/adin1110.c:1226: undefined reference to `phy_disconnect'
   ld: drivers/net/ethernet/adi/adin1110.o: in function `adin1110_adjust_link':
   drivers/net/ethernet/adi/adin1110.c:1077: undefined reference to `phy_print_status'
   ld: drivers/net/ethernet/adi/adin1110.o: in function `adin1110_ioctl':
   drivers/net/ethernet/adi/adin1110.c:790: undefined reference to `phy_do_ioctl'
   ld: drivers/net/ethernet/adi/adin1110.o:(.rodata+0xf60): undefined reference to `phy_ethtool_get_link_ksettings'
   ld: drivers/net/ethernet/adi/adin1110.o:(.rodata+0xf68): undefined reference to `phy_ethtool_set_link_ksettings'

Fixes: bc93e19d ("net: ethernet: adi: Add ADIN1110 support")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202402070626.eZsfVHG5-lkp@intel.com/
Cc: Lennart Franzen <lennart@lfdomain.com>
Cc: Alexandru Tachici <alexandru.tachici@analog.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: netdev@vger.kernel.org
Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Signed-off-by: David S. Miller <davem@davemloft.net>