Allow /dev/dma_heap directory to be readable

Allow everyone to read /dev/dma_heap so that they can query the set of
available heaps with the GetDmabufHeapList() API in libdmabufheap.
This patch fixes the following denials that happen when clients use the
API:

avc: denied { read } for name="dma_heap" dev="tmpfs" ino=369
scontext=u:r:mediaswcodec:s0 tcontext=u:object_r:dmabuf_heap_device:s0
tclass=dir permissive=0
9507:05-12 17:19:59.567  1647  1647 W com.android.systemui: type=1400
audit(0.0:93): avc: denied { read } for
comm=4E444B204D65646961436F6465635F name="dma_heap" dev="tmpfs" ino=369
scontext=u:r:platform_app:s0:c512,c768
tcontext=u:object_r:dmabuf_heap_device:s0 tclass=dir permissive=0
app=com.android.systemui

Test: manual
Bug: 184397788
Change-Id: I84672bc0be5b409cd49080501d0bf3c269ca610c
1 file changed