ti: common: am6: Add support for board description EEPROM

The AM654x EVM based on the TI K3 family of SoCs have an updated board
detection EEPROM structure, now comprising variable-sized TLV-type
records, containing a superset of what is already being provided on
earlier platforms such as DRA7. Add basic support for parsing the new
data structures contained on the base board into the common TI EEPROM
structure while also providing infrastructure that can be used later on
to parse data from additional EEPROMs such as the ones that are used on
daughtercards for this platform.

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