Move libgbm dep to the right place

main.rs doesn't use libgbm, but gpu_buffer does. Move the dep to the
right place. This wasn't noticed due to a bug in rust_*_host which
allows the dylib dependencies to be satisfied by host copies of the
libraries, instead of those built by the Android build system.

Change-Id: If0a46983ae3143fb5fa122d6a90fbc095235abbf
diff --git a/Android.bp b/Android.bp
index 3e3d2b9..64f097b 100644
--- a/Android.bp
+++ b/Android.bp
@@ -103,7 +103,6 @@
     shared_libs: [
         "libcap",
         "libepoxy",
-        "libgbm",
         "libminijail",
     ],
 }
diff --git a/gpu_buffer/Android.bp b/gpu_buffer/Android.bp
index b6082c4..9fd582d 100644
--- a/gpu_buffer/Android.bp
+++ b/gpu_buffer/Android.bp
@@ -12,6 +12,9 @@
         "libdata_model",
         "libsys_util",
     ],
+    shared_libs: [
+        "libgbm",  // added manually
+    ],
 }
 
 rust_library_host {
@@ -24,6 +27,9 @@
         "libdata_model",
         "libsys_util",
     ],
+    shared_libs: [
+        "libgbm",  // added manually
+    ],
 }
 
 // dependent_library ["feature_list"]