Set min_sdk_version to be part of mainline modules

Modules contributing mainline modules (APK/APEX) should set
min_sdk_version as well as apex_available.

- libstagefright_headers
- libstagefright_esds
- libstagefright_metadatautils
- libstagefright_mpeg2extractor
- libstagefright_m4vh263dec
- libstagefright_m4vh263enc

For now setting min_sdk_version doesn't change build outputs.
But build-time checks will be added soon.

Bug: 152655956
Test: m
Change-Id: I821b309ac5b4cfc7d83da69f6715fc327824cb66
diff --git a/media/ndk/Android.bp b/media/ndk/Android.bp
index 13db15c..9371353 100644
--- a/media/ndk/Android.bp
+++ b/media/ndk/Android.bp
@@ -35,6 +35,12 @@
 cc_library_headers {
     name: "media_ndk_headers",
     vendor_available: true,
+    apex_available: [
+        "//apex_available:platform",
+        "com.android.media",
+        "com.android.media.swcodec",
+    ],
+    min_sdk_version: "29",
     export_include_dirs: ["include"],
     host_supported: true,
     target: {