board: ti: j721e: Use EEPROM-based board detection

board: ti: j721e: Use EEPROM-based board detection

The TI J721E EVM system on module (SOM), the common processor board, and
the associated daughtercards have on-board I2C-based EEPROMs containing
board config data. Use the board detection infrastructure to do the
following:

1) Parse the J721E SOM EEPROM and populate items like board name, board
   HW and SW revision as well as board serial number into the TI common
   EEPROM data structure residing in SRAM scratch space
2) Check for presence of daughter card(s) by probing associated I2C
   addresses used for on-board EEPROMs containing daughter card-specific
   data. If such a card is found, parse the EEPROM data such as for
   additional Ethernet MAC addresses and populate those into U-Boot
   accordingly
3) Dynamically apply daughter card DTB overlays to the U-Boot (proper)
   DTB during SPL execution
4) Dynamically create an U-Boot ENV variable called name_overlays
   during U-Boot execution containing a list of daugherboard-specific
   DTB overlays based on daughercards found to be used during Kernel
   boot.

This patch adds support for the J721E system on module boards containing
the actual SoC ("J721EX-PM2-SOM", accessed via CONFIG_EEPROM_CHIP_ADDRESS),
the common processor board ("J7X-BASE-CPB"), the Quad-Port Ethernet
Expansion Board ("J7X-VSC8514-ETH"), the infotainment board
("J7X-INFOTAN-EXP") as well as for the gateway/Ethernet switch/industrial
expansion board ("J7X-GESI-EXP").

Signed-off-by: Andreas Dannenberg <dannenberg@ti.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>