i2c: designware: Manually set RESTART bit between messages

If both IC_EMPTYFIFO_HOLD_MASTER_EN and IC_RESTART_EN are set to 1, the
Designware I2C controller doesn't generate RESTART unless user specifically
requests it by setting RESTART bit in IC_DATA_CMD register.

Since IC_EMPTYFIFO_HOLD_MASTER_EN setting can't be detected from hardware
register, we must always manually set the restart bit between messages.

Signed-off-by: Chew, Chiau Ee <chiau.ee.chew@intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>