xorgproto: move pc files to libdir

xorgproto: move pc files to libdir

We fixed this two years go:
http://lists.openembedded.org/pipermail/openembedded-core/2018-June/151922.html

However xorgproto moved to meson and uses pkgconfig module to generate the .pc
which does not provide a method of omitting the libdir, which now means any
pc generated from meson using the module will always be mulitlib incompatible.

Signed-off-by: Jeremy A. Puhlman <jpuhlman@mvista.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>