Add apex_available and min_sdk_version to libip_checksum

Prepare to package libclat library and clatd binary into tethering
apex. This library is required.

Bug: 212345928
Test: build
Change-Id: I768c6358d9f4f15b37f73b3cfe2ff54a095a1bca
diff --git a/staticlibs/native/ip_checksum/Android.bp b/staticlibs/native/ip_checksum/Android.bp
index d7e195d..9878d73 100644
--- a/staticlibs/native/ip_checksum/Android.bp
+++ b/staticlibs/native/ip_checksum/Android.bp
@@ -37,4 +37,10 @@
     //
     // TODO: delete libnetutils from the VNDK in T, and remove this.
     vendor_available: true,
+
+    min_sdk_version: "30",
+    apex_available: [
+        "com.android.tethering",
+        "//apex_available:platform",
+    ],
 }