mate-applets fails to build on ppc64el.
On this architecture libcpupower is used instead of libcpufreq .
Looking at upstream, it seems that mate-applets completely switched to
libcpupower on all arch since kernel 4.7.
So I propose to follow that move by depending on libcpupower-dev and
remove patch 1000-fix-build-on-linux-4.7-or-newer.patch that suppose libcpufreq use :