Commit 7373cc02 introduced a workaround for a suboptimal choice in
wrpc-sw about global variables (that were "common").  Commit 9ff25f86
of wrpc-sw fixed it, so this removes the workaround (which, btw,
prevents compilation of ppsi as a submodule of current wrpc-sw).
Signed-off-by: Alessandro Rubini <rubini@gnudd.com>