Remove support for command-line args

We no longer support passing string arguments to a VM. Any
customization needed can be done by having the host communicate with
the VM after it starts.

Also start adding a header to provide the entry-point prototype for
better safety.

Bug: 249064104
Bug: 243513572
Test: atest MicrodroidTests MicrodroidHostTestCases
Change-Id: I0a1775f3b6a0b11c71c4831f6c380d96bb637c00
diff --git a/microdroid/vm_payload/Android.bp b/microdroid/vm_payload/Android.bp
index a68595f..925928e 100644
--- a/microdroid/vm_payload/Android.bp
+++ b/microdroid/vm_payload/Android.bp
@@ -31,3 +31,8 @@
         "libvm_payload",
     ],
 }
+
+cc_library_headers {
+    name: "vm_payload_headers",
+    export_include_dirs: ["include"],
+}