x86: Convert to use driver model timer

Convert all x86 boards to use driver model tsc timer.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/x86/dts/broadwell_som-6896.dts b/arch/x86/dts/broadwell_som-6896.dts
index a6b5d0f..194f0eb 100644
--- a/arch/x86/dts/broadwell_som-6896.dts
+++ b/arch/x86/dts/broadwell_som-6896.dts
@@ -3,6 +3,7 @@
 /include/ "skeleton.dtsi"
 /include/ "serial.dtsi"
 /include/ "rtc.dtsi"
+/include/ "tsc_timer.dtsi"
 
 / {
 	model = "Advantech SOM-6896";