xserver-xf86-config: fix do_install

for some reason wildcards don't work in current head. Error message was:

| DEBUG: Executing shell function do_install
| install: cannot stat `/home/Superandy/tmp/oe-core-eglibc/work/raspberrypi-angstrom-linux-gnueabi/xserver-xf86-config/0.1-r18/xorg.conf.d/*': No such file or directory