Ensure compile first to make avbtool work

Test: make host-unit-tests
Bug: 178591423
Change-Id: Ibac59430a1dff69117b16c44787c177501825986
diff --git a/fs_mgr/libfs_avb/Android.bp b/fs_mgr/libfs_avb/Android.bp
index 2f1ca70..45e7a30 100644
--- a/fs_mgr/libfs_avb/Android.bp
+++ b/fs_mgr/libfs_avb/Android.bp
@@ -100,6 +100,7 @@
     shared_libs: [
         "libcrypto",
     ],
+    compile_multilib: "first",
     data: [
         ":avbtool",
         ":fec",