USB: Configure Diag MDM instance on 90D9

On certain platforms like IVI where diag-router is used, we do
not expect an MDM to be attached in case of 90D9. Now to be able
to collect WLAN FW diag logs, we need to use the diag_mdm2
instance. So use "vendor.usb.diag_mdm.inst.name" property to
decide which instance name to bind, while keeping the default
value to "diag_mdm".

Change-Id: I53ddb2ab3540b3202c50927bf9c0e6b3e0434b0b
diff --git a/etc/init.qcom.usb.rc b/etc/init.qcom.usb.rc
index 7cdc013..3342bef 100644
--- a/etc/init.qcom.usb.rc
+++ b/etc/init.qcom.usb.rc
@@ -1,4 +1,4 @@
-# Copyright (c) 2011-2016, 2018-2020 The Linux Foundation. All rights reserved.
+# Copyright (c) 2011-2016, 2018-2021 The Linux Foundation. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
@@ -1425,7 +1425,7 @@
     write /config/usb_gadget/g1/idProduct 0x90D9
     write /config/usb_gadget/g1/functions/diag.diag/pid 0x90d9
     symlink /config/usb_gadget/g1/functions/${vendor.usb.diag.func.name}.diag /config/usb_gadget/g1/configs/b.1/f1
-    symlink /config/usb_gadget/g1/functions/${vendor.usb.diag.func.name}.diag_mdm /config/usb_gadget/g1/configs/b.1/f2
+    symlink /config/usb_gadget/g1/functions/${vendor.usb.diag.func.name}.${vendor.usb.diag_mdm.inst.name:-diag_mdm} /config/usb_gadget/g1/configs/b.1/f2
     symlink /config/usb_gadget/g1/functions/ffs.adb /config/usb_gadget/g1/configs/b.1/f3
     write /config/usb_gadget/g1/UDC ${sys.usb.controller}
     setprop sys.usb.state ${sys.usb.config}