systemd: Fix build on ppc

systemd: Fix build on ppc

ppc discovers an interesting issue in linking systemd where a library is
missing in link cmdline and linker barfs

./.libs/libsystemd-core.a(libsystemd_core_la-manager.o): In function
`manager_check_finished':
/builddir/build/BUILD/systemd-196/src/core/manager.c:2092: undefined
reference to `sd_notifyf'
collect2: error: ld returned 1 exit status

For more info see

https://bugzilla.redhat.com/show_bug.cgi?id=888255

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>