ARM: dts: stm32: add ethernet1 for STM32MP135F-DK board

ARM: dts: stm32: add ethernet1 for STM32MP135F-DK board

Ethernet1: RMII with crystal
Ethernet2: RMII with no cristal, need "phy-supply" property to work,
today this property was managed by Ethernet glue, but should be present
and managed in PHY node. So I will push second Ethernet in next step.

PHYs used are SMSC (LAN8742A)

Signed-off-by: Christophe Roullier <christophe.roullier@foss.st.com>
Reviewed-by: Marek Vasut <marex@denx.de>
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>