Update eeprom_execute_command() and related code to accommodate both layout
aware and layout unaware functions.

No functional changes.

Cc: Heiko Schocher <hs@denx.de>
Cc: Marek Vasut <marex@denx.de>
Cc: Simon Glass <sjg@chromium.org>
Cc: Igor Grinberg <grinberg@compulab.co.il>
Cc: Tom Rini <trini@konsulko.com>
Signed-off-by: Nikita Kiryanov <nikita@compulab.co.il>
[trini: Make eeprom_execute_command have ulong for i2c_addr]
Signed-off-by: Tom Rini <trini@konsulko.com>