sepolicy: minigbm_msm: fix vendor.minigbm.debug prop access denials am: 4746684811 am: e6ebfb6e97 am: 2352d0e529

Original change: https://android-review.googlesource.com/c/device/linaro/dragonboard/+/2752086

Change-Id: I27de88ca85d87aa09a7a1a403f0e418fc1fc8383
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>