msm: mdss: clear BTA_DONE interrupt during DSI read operations

In cases where DSI DMA done operation is performed but isr is
not triggered due to CPU delays, we clear only the DMA_DONE
interrupt. There is a possibility of a DSI read operation for
DSI command mode panels where the DMA_DONE interrupt is cleared and
DSI link clocks are turned off. After some time, the DSI isr gets
triggered for BTA_DONE interrupt and since DSI link clocks are off,
this causes an interrupt storm due to BTA_DONE interrupt not getting
cleared. Clear the BTA_DONE interrupt as well for cases where DMA_DONE
operation is done but isr not getting triggered.

Change-Id: Iceb02e6dd78f4bbf313e2b4d252d6a30699619f0
Signed-off-by: Padmanabhan Komanduru <pkomandu@codeaurora.org>