[ARM] 4457/2: davinci: GPIO support

Support GPIO driver for TI DaVinci SoC

Signed-off-by: Vladimir Barinov <vbarino@ru.mvista.com>
Acked-by: David Brownell <david-b@pacbell.net>
Acked-by: Kevin Hilman <khilman@mvista.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>