i2c: rewrite mvtwsi, support orion5x and kirkwood

This rewrite of the mvtwsi driver is 25% smaller and much
faster and simpler than the previous code.

Signed-off-by: Albert Aribaud <albert.aribaud@free.fr>
Acked-by: Prafulla <Wadaskar&lt;prafulla@marvell.com>
Acked-by: Heiko <Schocher&lt;hs@denx.de>