ARM: 6337/2: AB8500 I2C platform configuration and irq

This patch adds the platform part of the AB8500 PRCMU I2C
access driver. The old irq name AB4500 is changed to AB8500.

Signed-off-by: Mattias Wallin <mattias.wallin@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>