ARM: renesas: Enable rswitch, serdes and PHY driver on R8A779F0 S4 Spider

Enable Renesas RSwitch driver, matching SERDES PHY driver and Marvell
10G ethernet PHY driver in R8A779F0 S4 Spider board configuration to
make ethernet available via the RSwitch ports.

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>