msm: mdss: do not report overflow errors during read commands

During a DSI DMA read command transaction, it is expected to have
DSI FIFO overflow if the read operation duration exceeds one BLLP
line time frame. Make sure not to trigger DSI FIFO overflow recovery
sequence for such cases where DSI FIFO overflow error is masked.

Change-Id: I0762a0f51d580a44cfa24ffac60cc465c241c733
Signed-off-by: Padmanabhan Komanduru <pkomandu@codeaurora.org>