i2c-msm-v2: QUP I2C does not support 50MHz source frequency

MSM targets does not supports the source frequency of 50MHz.
This patch removes the functionality associated with above
source frequency from I2C driver.

Change-Id: I0085cb4a6ace0f02f7cea1707323b8f8ba00253f
Signed-off-by: Ankit Gupta <ankgupta@codeaurora.org>