ARM: dts: stm32: Describe PHY LEDs in DH STM32MP13xx DHCOR DHSBC board DT

ARM: dts: stm32: Describe PHY LEDs in DH STM32MP13xx DHCOR DHSBC board DT

The RTL8211 PHY on DH STM32MP13xx DHCOR DHSBC carrier board supports HW
LED offload, the LEDs can be configured on link at 10/100/1000 line rate
and on RXTX activity. There are two PHYs on this board, each only has two
out of three LEDs connected to the PHY LED outputs. Describe this hardware
configuration in DT.

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