gta4xl: add missing bluetooth firmware

* How did I miss this ...

Change-Id: I2e70907c9e3be001ab7d324eef5c1fc778d8e68b
diff --git a/proprietary-files.txt b/proprietary-files.txt
index 03d3834..47896cf 100644
--- a/proprietary-files.txt
+++ b/proprietary-files.txt
@@ -13,6 +13,9 @@
 vendor/firmware/cs35l41-dsp1-spk-prot.wmfw
 vendor/firmware/cs35l41-dsp1-spk-prot-calib.bin
 
+## Bluetooth Firmware
+vendor/etc/wifi/mx140_bt.hcf
+
 ## Camera dependencies
 vendor/lib/libexynoscamera3.so
 vendor/lib64/libexynoscamera3.so