Mark libjpeg vendor_available.

libjpeg belongs to vndk-cap. Mark it vendor_available to enable vndk
abi stability checks on it.

Details: https://android-review.googlesource.com/368372

Test: mm -j64

Bug: 38244611

Change-Id: Ie1be03da40624564a0d9e05fca7460911a3e5f50
diff --git a/Android.bp b/Android.bp
index 72d919c..508932c 100644
--- a/Android.bp
+++ b/Android.bp
@@ -173,6 +173,7 @@
 // Also build as a shared library.
 cc_library {
     name: "libjpeg",
+    vendor_available: true,
     defaults: ["libjpeg-defaults"],
     export_include_dirs: ["."],
 }