buildroot

xserver_xorg-server: fix dependency with dbus

If dbus and udev are enabled. Xorg link with both:

$ arm-linux-readelf -d usr/bin/X | grep NEEDED
 0x00000001 (NEEDED)                     Shared library: [libdbus-1.so.3]
 0x00000001 (NEEDED)                     Shared library: [libpthread.so.0]
 0x00000001 (NEEDED)                     Shared library: [libudev.so.1]
[...]

Signed-off-by: Jérôme Pouiller <jezz@sysmic.org>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>