SPI: Put SPI devices on their own bus ...

This patch adds a SPI bus on which the SPI devices and drivers register.
This makes it cleaner as SPI devices won't accidently end up probed by
a platform_device driver.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

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>