i2c-msm-v2: correct the start stop condition in certain cases

Account for i2c message buffers which requires
multiple qup buffers and tags, this patch corrects
the algorithm to avoid asserting a STOP TAG at the end
of such buffers.

Change-Id: Ic0eb106d4743972f039728e2ebfcbbf68a5e87dd
Signed-off-by: Ankit Gupta <ankgupta@codeaurora.org>