ARM: 5852/1: Add COH 901 318 DMA driver platform config for U300

This adds platform configuration for the COH 901 318 DMA driver
for the U300 series mobile platforms.

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