GPS: define LOC_HIDL_VERSION

Used by GPS HAL to enable loading of "vendor enhanced" code.

Issue: FP3-A12#22
Test: run vts -m vts_treble_vintf_vendor_test -t DeviceManifest/SingleManifestTest#HalsAreServed/0
Change-Id: I9bac4a89ba20e74de1e261ba2f32fa1c951994e1
(cherry picked from commit c1e2745f9ee24353167794e151f88392a63ee665)
diff --git a/device.mk b/device.mk
index fa14440..a32e05a 100644
--- a/device.mk
+++ b/device.mk
@@ -454,6 +454,7 @@
 
 # GPS
 BOARD_VENDOR_QCOM_GPS_LOC_API_HARDWARE := default
+LOC_HIDL_VERSION := 4.0
 
 PRODUCT_PACKAGES += \
 	android.hardware.gnss@2.1-impl-qti:64 \