gptfdisk: Make libgptf visible to Nvidia bootctrl

Change-Id: I907447b4b84abcc2e3f902798feacc6fde6adb42
diff --git a/Android.bp b/Android.bp
index 35c3bec..29cd005 100644
--- a/Android.bp
+++ b/Android.bp
@@ -89,6 +89,7 @@
     srcs: lib_common_srcs + ["diskio-unix.cc"],
 
     shared_libs: ["libext2_uuid"],
+    visibility: ["//hardware/nvidia/boot_control/nvpayload_update"],
 }
 
 cc_library_static {