i2c-msm-v2: correct end of message detection

Correct boundary case for end of message detection for buffers of
255 bytes. The check for max buffer size uses greater than rather
than the required greater or equal.

Change-Id: Icf94a33b8884756b6dc9515f7f61ebf154116435
Signed-off-by: Houston Hoffman <hhoffman@codeaurora.org>