Add another option for the ethernet0 pins.
It is almost identical to ethernet0_rgmii_pins_c apart from TXD0/1.

This is used on the Phycore STM32MP1.
Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>