msm: camera: Sensor specific I2C speed implementation.

I2C frequency selection is done based on requested frequency.
Added 100Khz, 400Khz and custom needed options.

Change-Id: Ibb639923472f0d1f5c3d9c5de11b65270a1f111f
Signed-off-by: Rajesh Bondugula <rajeshb@codeaurora.org>