Update Coral SVN to 21
Bug: 153882927

Change-Id: Ic2d5a6762e84a6fe50b1c782e2069e009c349cd7
(cherry picked from commit 96027182fe9eabec8c340f3f5b6761d577ff4da1)
diff --git a/device.mk b/device.mk
index 7fdf7d1..9380387 100644
--- a/device.mk
+++ b/device.mk
@@ -944,7 +944,7 @@
 
 # Increment the SVN for any official public releases
 PRODUCT_PROPERTY_OVERRIDES += \
-	ro.vendor.build.svn=20
+	ro.vendor.build.svn=21
 
 PRODUCT_COPY_FILES += \
     $(LOCAL_PATH)/powerhint.json:$(TARGET_COPY_OUT_VENDOR)/etc/powerhint.json