target: msm8996: Fix DSI kickoff timeout error

When enabling early animation on DSI display, kernel
will report DSI interface kickoff timeout problem once
starting handoff stuff. This is caused by LK has cleared
DSI interrupts while kernel needs to enable these interrupts.
So revert the clear operation in this fix.

CRs-Fixed: 2224864
Change-Id: Idb1765be197d3430e8308910d6802eccf7405da4
Signed-off-by: Guchun Chen <guchunc@codeaurora.org>