i2c-msm-v2: Add NULL pointer check for DMA descriptor

Add NULL pointer check for RX/TX DMA descriptors to avoid
NULL dereference.

Change-Id: I71443204e79eb1afc37a6b312cf4aa9adcaa22c6
Signed-off-by: Shrey Vijay <shreyv@codeaurora.org>
1 file changed