Allow dumpsys to read total DMA-BUF heap pool size

These permissions are added to allow dumpsys to read
/sys/kernel/dma_heap/total_pools_kb.

Fixes the following sepolicy denials:
avc: denied { read } for name="total_pools_kb" dev="sysfs" ino=3252
scontext=u:r:system_server:s0 tcontext=u:object_r:sysfs:s0 tclass=file permissive=1
avc: denied { open } for path="/sys/kernel/dma_heap/total_pools_kb"
dev="sysfs" ino=3252 scontext=u:r:system_server:s0 tcontext=u:object_r:sysfs:s0
tclass=file permissive=1
avc: denied { getattr } for path="/sys/kernel/dma_heap/total_pools_kb"
dev="sysfs" ino=3252 scontext=u:r:system_server:s0 tcontext=u:object_r:sysfs:s0
tclass=file permissive=1

Bug: 167709539
Test: dumpsys meminfo
Change-Id: I1c15b41b067da84a7b629cafe27972f30c86ae27
diff --git a/private/genfs_contexts b/private/genfs_contexts
index 960110f..05dc06f 100644
--- a/private/genfs_contexts
+++ b/private/genfs_contexts
@@ -148,6 +148,7 @@
 genfscon sysfs /power/wake_lock u:object_r:sysfs_wake_lock:s0
 genfscon sysfs /power/wake_unlock u:object_r:sysfs_wake_lock:s0
 genfscon sysfs /kernel/memory_state_time u:object_r:sysfs_power:s0
+genfscon sysfs /kernel/dma_heap u:object_r:sysfs_dma_heap:s0
 genfscon sysfs /kernel/ion u:object_r:sysfs_ion:s0
 genfscon sysfs /kernel/ipv4 u:object_r:sysfs_ipv4:s0
 genfscon sysfs /kernel/mm/transparent_hugepage u:object_r:sysfs_transparent_hugepage:s0