Define vintf fragment as a module

Define vintf fragment as a module, so it can be used from multiple
soong-defined modules.

Bug: 322089980
Test: aosp_cf_x86_64_phone build succeeded
(cherry picked from https://android-review.googlesource.com/q/commit:8c1af351129febcebea9ddc5f8e584a6a6a3bd97)
Change-Id: I817efd443e49439e4134fca8bd3fd034bbbcc3cc
diff --git a/wpa_supplicant/aidl/Android.bp b/wpa_supplicant/aidl/Android.bp
index 2175462..d523630 100644
--- a/wpa_supplicant/aidl/Android.bp
+++ b/wpa_supplicant/aidl/Android.bp
@@ -59,9 +59,10 @@
     ],
 }
 
-filegroup {
+vintf_fragment {
     name: "android.hardware.wifi.supplicant.xml",
-    srcs: ["android.hardware.wifi.supplicant.xml"],
+    src: "android.hardware.wifi.supplicant.xml",
+    soc_specific: true,
 }
 
 soong_config_module_type {