omap3: i2c: correct register

The register names and offset were not correct as per the TRM for OMAP3530
and OMAP3630.  Correct the naing and offsets per the documentation

Signed-off-by: Adam Ford <aford173@gmail.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Heiko Schocher <hs@denx.de>