t210: lp0_resume: clear the MC_INTSTATUS if MC_INTMASK was 0

The MC/SMMU should be resumed by the kernel. And the unexpected value
in the MC_INTSTATUS should be cleared before that. Or it will cause
some noisy MC interrupt once we enable the IRQ in the kernel.

BUG=chrome-os-partner:46796
BRANCH=none
TEST=LP0 suspend/resume test and the EMEM decode/arbitration errors
     should not be observed on resume.

Change-Id: I4d34905c04effd54d0d0edf8809e192283db2ca3
Signed-off-by: Joseph Lo <josephl@nvidia.com>
Reviewed-on: https://chromium-review.googlesource.com/309248
Reviewed-by: Tom Warren <twarren@nvidia.com>
Reviewed-by: Andrew Bresticker <abrestic@chromium.org>
Commit-Queue: Joseph Lo <yushun.lo@gmail.com>
Tested-by: Joseph Lo <yushun.lo@gmail.com>
1 file changed