ARM: DRA7: AMxx: Make sure that the SPL always reads the configuration EEPROM

The bootrom may corrupt the area of SRAM used to store the ti_common_eeprom
structure. This patch makes sure that it's always read after a reset, even
if a valid MAGIC number is found in the SRAM.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>