xorg-server: enable dpms by default

If you got the balls for Xorg, DPMS shouldn't hurt too much. Besides,
xf86-video-siliconmotion really needs it (null-pointer function call
otherwise).

package/xorg-server/Makefile

@@ -43,9 +43,9 @@ CONFIGURE_ARGS+=	\
 			--enable-xv \
 			--enable-xaa \
 			--enable-vgahw \
+			--enable-dpms \
 			--disable-aiglx \
 			--disable-config-hal \
-			--disable-dpms \
 			--disable-glx \
 			--disable-xace \
 			--disable-xephyr \