xserver-kdrive: compile xserver without dtrace support

xserver-kdrive: compile xserver without dtrace support

Cross compiling of xserver-kdrive fails if dtrace is enabled. Configure
script enables dtrace automatically if dtrace binary exists. xserver-kdrive
compiling was failed if systemtap package was builded beforehand because
systemtap provides dtrace binary.

Signed-off-by: Lauri Hintsala <lauri.hintsala@bluegiga.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>