Export missing audio volume properties

The following properties are used in AudioService:

ro.config.alarm_vol_default
ro.config.alarm_vol_steps
ro.config.media_vol_default
ro.config.system_vol_default
ro.config.system_vol_steps
ro.config.vc_call_vol_default

Test: properties can be set from vendor with PRODUCT_COMPATIBLE_PROPERTY_OVERRIDE := true

Change-Id: Ib90103173989fcb0723f3d8465df3cd03334cc53
diff --git a/private/property_contexts b/private/property_contexts
index a63ac64..0f5221d 100644
--- a/private/property_contexts
+++ b/private/property_contexts
@@ -382,10 +382,16 @@
 ro.com.android.dataroaming     u:object_r:exported3_default_prop:s0 exact bool
 ro.com.android.prov_mobiledata u:object_r:exported3_default_prop:s0 exact bool
 
-ro.config.alarm_alert        u:object_r:systemsound_config_prop:s0 exact string
-ro.config.media_vol_steps    u:object_r:systemsound_config_prop:s0 exact int
-ro.config.notification_sound u:object_r:systemsound_config_prop:s0 exact string
-ro.config.ringtone           u:object_r:systemsound_config_prop:s0 exact string
+ro.config.alarm_alert         u:object_r:systemsound_config_prop:s0 exact string
+ro.config.alarm_vol_default   u:object_r:systemsound_config_prop:s0 exact int
+ro.config.alarm_vol_steps     u:object_r:systemsound_config_prop:s0 exact int
+ro.config.media_vol_default   u:object_r:systemsound_config_prop:s0 exact int
+ro.config.media_vol_steps     u:object_r:systemsound_config_prop:s0 exact int
+ro.config.notification_sound  u:object_r:systemsound_config_prop:s0 exact string
+ro.config.ringtone            u:object_r:systemsound_config_prop:s0 exact string
+ro.config.system_vol_default  u:object_r:systemsound_config_prop:s0 exact int
+ro.config.system_vol_steps    u:object_r:systemsound_config_prop:s0 exact int
+ro.config.vc_call_vol_default u:object_r:systemsound_config_prop:s0 exact int
 
 ro.config.per_app_memcg u:object_r:exported3_default_prop:s0 exact bool