i2c: davinci: misc. cleanups: remove MOD_REG_BIT and IO_ADDRESS usage

Cleanup the DaVinci I2C driver. Remove MOD_REG_BIT macro.
Also use ioremap instead of IO_ADDRESS macro.

Signed-off-by: Chaithrika U S <chaithrika@ti.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>