msm: camera: extend reg_settings_t structure

extend reg_settings_t structure to be able
to add more functionality in actuator driver
like poll and delay between two write
i2c transactions because some actuator
drivers need of this operations

Change-Id: I792d1757e53c62f2eeef73d1b97f5e5b7ad13b1c
Signed-off-by: Vasko Kalanoski <vaskok@codeaurora.org>