CRAS: cras_shm: Fix double munmap calls in cras_audio_shm_destroy

CL:1656635 introduces split version `cras_audio_shm`.
For unsplit version cras_audio_shm`, `shm->samples` is pointed to the last
chunk of memory owned by `shm->header`.
We shouldn't call `munmap` for `shm->samples` in `cras_audio_shm_destroy`
for this version of `cras_audio_shm`.

BUG=chromium:968724, b:136129302
TEST=1. Play audio in ARC++
     2. Close the app
     3. Play audio again in ARC++
TEST=1. Play audio in ARC++
     2. Play audio in Chrome and trigger audio focus
     3. Play audio again in ARC++

Change-Id: I1cbb58d2dd3bbe1940c693259ce7c2239d02ee06
Reviewed-on: https://chromium-review.googlesource.com/1679956
Tested-by: Chih-Yang Hsia <paulhsia@chromium.org>
Commit-Ready: Chih-Yang Hsia <paulhsia@chromium.org>
Legacy-Commit-Queue: Commit Bot <commit-bot@chromium.org>
Reviewed-by: Cheng-Yi Chiang <cychiang@chromium.org>
1 file changed