Remove ndk_platform backend. Use the ndk backend.

The ndk_platform backend will soon be deprecated because the ndk backend
can serve the same purpose. This is to eliminate the confusion about
having two variants (ndk and ndk_platform) for the same 'ndk' backend.

Bug: 161456198
Test: m
Change-Id: I3bcfc77e86a95b64ff80587c3d7f68be5b5100b8
diff --git a/microdroid/keymint/Android.bp b/microdroid/keymint/Android.bp
index 6d651b9..a0bbaf4 100644
--- a/microdroid/keymint/Android.bp
+++ b/microdroid/keymint/Android.bp
@@ -15,7 +15,7 @@
         "-Wextra",
     ],
     shared_libs: [
-        "android.hardware.security.keymint-V1-ndk_platform",
+        "android.hardware.security.keymint-V1-ndk",
         "lib_android_keymaster_keymint_utils",
         "libbase",
         "libbinder_ndk",