The ethernet MAC EEPROM is not populated on the SoM itself, it has to be
populated on each carrier board. Move the EEPROM into the correct place
in DTs, i.e. the carrier board DTs. Add label to the EEPROM too.

Fixes: 7e76f82a ("ARM: dts: stm32: Split Avenger96 into DHCOR SoM and Avenger96 board")
Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>