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/hostapd/Android.bp b/hostapd/Android.bp
index 8a7dacf..54047f2 100644
--- a/hostapd/Android.bp
+++ b/hostapd/Android.bp
@@ -348,9 +348,10 @@
 }
 
 // This manifest can used by a vendor apex module for hostapd as well.
-filegroup {
+vintf_fragment {
     name: "android.hardware.wifi.hostapd.xml",
-    srcs: ["android.hardware.wifi.hostapd.xml"],
+    src: "android.hardware.wifi.hostapd.xml",
+    soc_specific: true,
 }
 
 // Generated by building hostapd_cli and printing LOCAL_SRC_FILES