cifs-utils: inherit pkgconfig

* it fails in do_configure without it
  configure.ac:99: error: possibly undefined macro: AC_MSG_ERROR
       If this token and others are legitimate, please use m4_pattern_allow.
       See the Autoconf documentation.
  configure.ac:140: error: possibly undefined macro: AC_MSG_WARN
  autoreconf: sysroots/x86_64-linux/usr/bin/autoconf failed with exit status: 1

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>