i2c: iproc: Add i2c repeated start capability

Enable handling of i2c repeated start. The current code
handles a multi msg i2c transfer as separate i2c bus
transactions. This change will now handle this case
using the i2c repeated start protocol. The number of msgs
in a transfer is limited to two, and must be a write
followed by a read.

Signed-off-by: Lori Hikichi <lori.hikichi@broadcom.com>
Signed-off-by: Rayagonda Kokatanur <rayagonda.kokatanur@broadcom.com>
Signed-off-by: Icarus Chau <icarus.chau@broadcom.com>
Signed-off-by: Ray Jui <ray.jui@broadcom.com>
Signed-off-by: Shivaraj Shetty <sshetty1@broadcom.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>