Add radio_ext aidl to compatibility matrix

Test: manual
Bug: 285459428
Change-Id: Ic07926b2af7ea980575f4909ebe742efeb39ef82
diff --git a/modem/radio_ext/radio_ext.mk b/modem/radio_ext/radio_ext.mk
new file mode 100644
index 0000000..6750fdd
--- /dev/null
+++ b/modem/radio_ext/radio_ext.mk
@@ -0,0 +1,5 @@
+PRODUCT_SOONG_NAMESPACES += vendor/google/interfaces
+PRODUCT_PACKAGES += vendor.google.radio_ext-service
+DEVICE_PRODUCT_COMPATIBILITY_MATRIX_FILE += device/google/gs-common/modem/radio_ext/compatibility_matrix.xml
+
+BOARD_VENDOR_SEPOLICY_DIRS += device/google/gs-common/modem/radio_ext/sepolicy