use loff_t for file offsets ...

This is a first step for 64bit file support: Make the file sizes/offsets
64bit.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

eeprom: add at25 eeprom driver ...

This commit adds support for most spi eeproms, such as the
Atmel at25 models.

Signed-off-by: Hubert Feurstein <h.feurstein@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>