images: Add 420dpi symlink

Change-Id: If184d3e3c5e4545e8baba665366b59390718ac02
Signed-off-by: Christopher N. Hesse <raymanfx@gmail.com>
(cherry picked from commit 70e7015d73b8fdd5258732863012f7b06d8347f5)
diff --git a/charger/images/420dpi b/charger/images/420dpi
new file mode 120000
index 0000000..17ef829
--- /dev/null
+++ b/charger/images/420dpi
@@ -0,0 +1 @@
+xxhdpi
\ No newline at end of file