It's only required for the proxy helper.

Add a new option for the proxy helper rather than enabling it
implicitly.

Change-Id: I95b73fca625529e99d16b0a64e01c65c0c1d43f2
Signed-off-by: Peter Foley <pefoley@google.com>
Message-Id: <20230503130757.863824-1-pefoley@google.com>
[C.S.: - Resolve merge conflict. ]
Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>