i2c-msm-v2: Handle Null pointer de-reference

Zero message may be passed causing null pointer de-reference.
Adding check on the number of messages passed to handle the issue.

Change-Id: I7cef6dd2070c5eaaa748698c45540f8aa1d96116
Signed-off-by: Vipin Deep Kaur <vkaur@codeaurora.org>