i2c: sirf: support reverse direction of address

if users set I2C_M_REV_DIR_ADDR, revert the direction of address.

Signed-off-by: Zhiwu Song <Zhiwu.Song@csr.com>
Signed-off-by: Rongjun Ying <rongjun.ying@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>