ARM: stm32: Read values from M24256 write-lockable page on STM32MP13xx DHCOR

ARM: stm32: Read values from M24256 write-lockable page on STM32MP13xx DHCOR

The STM32MP13xx DHCOR SoM is populated with M24256 EEPROM that contains
an additional write-lockable page called ID page, which is populated with
a structure containing ethernet MAC addresses, DH item number and DH serial
number.

Read out the MAC address from the WL page between higher priority SoC fuses
and lower priority plain EEPROM storage area. Read out the DH item and serial
numbers and set environment variables accordingly.

Signed-off-by: Marek Vasut <marek.vasut@mailbox.org>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>