Disable RPC due to licensing issues

In Bookwork to build with rpc support libtirpc3 is used which has pieces
of BSD-4 code. In Bullseye this was handled by libc6-dev, but in Bookworm
is no handled.

To avoid the issue, disable the RPC support.

Signed-off-by: Walter Lozano <walter.lozano@collabora.com>