Generate apex_available from c2a instead of a patch

Test: Run c2a
Test: Build
Change-Id: I7b66c50dac35b73634324d2555259e997a7a6644
diff --git a/patches/Android.bp.patch b/patches/Android.bp.patch
index c124dc0..071947f 100644
--- a/patches/Android.bp.patch
+++ b/patches/Android.bp.patch
@@ -2,7 +2,7 @@
 index 41d67cc..277296f 100644
 --- b/Android.bp
 +++ a/Android.bp
-@@ -64,10 +64,14 @@
+@@ -64,7 +64,7 @@
          "range_inclusive",
          "serde_derive",
          "std_atomic",
@@ -11,10 +11,3 @@
          "systemtime_checked_add",
      ],
      proc_macros: ["libserde_derive"],
-+    apex_available: [
-+        "//apex_available:platform",
-+        "com.android.virt",
-+    ],
- }
- 
- // dependent_library ["feature_list"]