move modem dump to gs-common

Bug: 250475732
Test: adb bugreport
Change-Id: Id6dc2ef02d5e32b71de1b618e5588c202a2b6243
diff --git a/modem/modem.mk b/modem/modem.mk
new file mode 100644
index 0000000..fe4633d
--- /dev/null
+++ b/modem/modem.mk
@@ -0,0 +1,3 @@
+BOARD_VENDOR_SEPOLICY_DIRS += device/google/gs-common/modem/sepolicy
+
+PRODUCT_PACKAGES += dump_modem.sh