ARC: [dts] Introduce Timer bindings

ARC Timers have historically been probed directly.
As precursor to start probing Timers thru DT introduce these bindings
Note that to keep series bisectable, these bindings are not yet used in
code.

Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: devicetree@vger.kernel.org
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

arch/arc/boot/dts/skeleton.dtsi

@@ -30,6 +30,20 @@
 		};
 	};
 
+	/* TIMER0 with interrupt for clockevent */
+	timer0 {
+		compatible = "snps,arc-timer";
+		interrupts = <3>;
+		interrupt-parent = <&core_intc>;
+		clocks = <&core_clk>;
+	};
+
+	/* TIMER1 for free running clocksource */
+	timer1 {
+		compatible = "snps,arc-timer";
+		clocks = <&core_clk>;
+	};
+
 	memory {
 		device_type = "memory";
 		reg = <0x80000000 0x10000000>;	/* 256M */