pkgconfig: Fix libpci.pc for static linking

pkgconfig: Fix libpci.pc for static linking

The libpci.pc file does not seem to be correct for static linking.

  $ pkg-config --libs --static libpci
  -lpci

It brings no dependencies while -lresolv (and likely -lz) seems needed:

  /usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/
   libpci.a(names-net.o):function pci_id_net_lookup:
   error: undefined reference to '__res_query'

Something like:

  Libs.private: -lresolv -lz

Signed-off-by: Guillem Jover <guillem@hadrons.org>