[CEC Configuration] Move master configuration from '/product/etc' to '/system/etc'

Master configuration should actually be available for all Android devices.

Bug: 168020131
Bug: 174349652
Test: atest HdmiCecConfig; also flashed and smoke tested a device
Change-Id: I79dee4798a4d2405505f58e89d78b152cdc82fd7
diff --git a/Android.bp b/Android.bp
index 9493733..b1eb4a5 100644
--- a/Android.bp
+++ b/Android.bp
@@ -604,8 +604,9 @@
     ],
     required: [
         "framework-platform-compat-config",
-        // TODO: remove gps_debug and protolog.conf.json when the build system propagates "required" properly.
+        // TODO: remove gps_debug, cec_config.xml and protolog.conf.json when the build system propagates "required" properly.
         "gps_debug.conf",
+        "cec_config.xml",
         "icu4j-platform-compat-config",
         "libcore-platform-compat-config",
         "protolog.conf.json.gz",