Mark libs as double_loadable

libs(libasyncio libmemtrack libprocinfo libusbhost) have
vendor variants and they are also used by LLNDK(libmediandk)
which means these libs can be double-loaded.

deps:
- libmediandk -> libmedia_jni -> libmtp -> libasyncio
- libmediandk -> libmedia_jni -> libandroid_runtime -> libmemtrack
- libmediandk -> libmedia_jni -> libandroid_runtime -> libdebuggerd_client -> libprocinfo
- libmediandk -> libmedia_jni -> libmtp -> libusbhost

Bug: 121280180
Test: m -j
Change-Id: I2c2b5d67cf47b85a2aa8c08f85c7e1a84490cf4e

libasyncio/Android.bp

@@ -27,6 +27,7 @@ cc_library {
     name: "libasyncio",
     defaults: ["libasyncio_defaults"],
     vendor_available: true,
+    double_loadable: true,
     recovery_available: true,
     host_supported: true,
     srcs: [

libmemtrack/Android.bp

@@ -6,6 +6,7 @@ cc_library_shared {
     vndk: {
         enabled: true,
     },
+    double_loadable: true,
     srcs: ["memtrack.cpp"],
     export_include_dirs: ["include"],
     local_include_dirs: ["include"],

libprocinfo/Android.bp

@@ -31,6 +31,7 @@ cc_library {
     vndk: {
         enabled: true,
     },
+    double_loadable: true,
     host_supported: true,
     srcs: [
         "process.cpp",

libusbhost/Android.bp

@@ -20,6 +20,7 @@ cc_library {
     vndk: {
         enabled: true,
     },
+    double_loadable: true,
     host_supported: true,
     srcs: ["usbhost.c"],
     cflags: ["-Werror"],