mfd: wcd9xxx-core: write same register with multiple values

WCD codec has CPE and connected in i2c interface with MSM.
CPE image download happens through codec register write.

Write same register with multiple values. All these values
are sent to slave in single i2c message execution.

Change-Id: I71b0fe6f94f064b66f6370cc8a098b3f4161c6e5
Signed-off-by: Viraja Kommaraju <virajak@codeaurora.org>