libeffects: Add host support for reverb modules

- Removed __unused that is not supported by host toolchain
- Removed unused libdl dependency from libreverbwrapper

Bug: 180116440
Test: run reverb_benchmark on host

Change-Id: Id44248fe3ad77650199bc624ba32e8ad373b4abe
diff --git a/media/libeffects/lvm/benchmarks/Android.bp b/media/libeffects/lvm/benchmarks/Android.bp
index 60a9772..8a25b85 100644
--- a/media/libeffects/lvm/benchmarks/Android.bp
+++ b/media/libeffects/lvm/benchmarks/Android.bp
@@ -28,6 +28,7 @@
 cc_benchmark {
     name: "reverb_benchmark",
     vendor: true,
+    host_supported: true,
     include_dirs: [
         "frameworks/av/media/libeffects/lvm/wrapper/Reverb",
     ],