Enable device builds for libpffft

Bug: 169202556
Test: Builds
Change-Id: I8eb3fdde07043779464301350af5a756f5c808f9
diff --git a/Android.bp b/Android.bp
index dad90bb..d953669 100644
--- a/Android.bp
+++ b/Android.bp
@@ -1,5 +1,7 @@
 cc_library_static {
     name: "libpffft",
+    // vendor needed for libpreprocessing effects.
+    vendor: true,
     srcs: [
         "pffft.c",
         "pffft_common.c",
@@ -7,9 +9,14 @@
     local_include_dirs: ["."],
     export_include_dirs: ["."],
     host_supported: true,
-    device_supported: false,
     visibility: ["//external/webrtc:__subpackages__"],
+    cflags: [
+        "-Wno-#pragma-messages",
+    ],
     arch: {
+        arm: {
+            cflags: ["-DPFFFT_ENABLE_NEON"],
+        },
         arm64: {
             cflags: ["-DPFFFT_ENABLE_NEON"],
         },