I2C: mv_i2c: add multi bus support

Add the ability to support multiple i2c bus for mv_i2c

Acked-by: Heiko Schocher <hs@denx.de>
Acked-by: Prafulla Wadaskar <prafulla@marvell.com>
Signed-off-by: Lei Wen <leiwen@marvell.com>