Make gfxstream static library visible

This makes the static library visible, so we can create static linked
releases.

Bug: 335734830
Change-Id: I64b839a011d14bf2d6c1cb2d0bfd138e644fb4cf
diff --git a/host/BUILD.bazel b/host/BUILD.bazel
index effb33f..242b3e4 100644
--- a/host/BUILD.bazel
+++ b/host/BUILD.bazel
@@ -185,6 +185,7 @@
         "virtio-gpu-gfxstream-renderer.cpp",
     ],
     linkshared = True,
+    visibility = ["//visibility:public"],
     deps = [
         ":gfxstream_backend_static",
         "//hardware/google/aemu/base:aemu-base",