ti: common: dra7: Add standard access for board description EEPROM

DRA7 EVM revH and later EVMs have EEPROM populated that can contain board
description information such as name, revision, DDR definition, etc. Adding
support for this EEPROM format.

Acked-by: Nishanth Menon <nm@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>