ARM: sun6i: Enable ARM arch timers

The A31 has non-initialized architected timers, without CNTFRQ or CNTVOFF set
by the Allwinner's bootloader.

Use the new DT property for such case, and enable the arch timers.
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>

arch/arm/boot/dts/sun6i-a31.dtsi

@@ -87,6 +87,16 @@
 		};
 	};
 
+	timer {
+		compatible = "arm,armv7-timer";
+		interrupts = <GIC_PPI 13 (GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>,
+			     <GIC_PPI 14 (GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>,
+			     <GIC_PPI 11 (GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>,
+			     <GIC_PPI 10 (GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>;
+		clock-frequency = <24000000>;
+		arm,cpu-registers-not-fw-configured;
+	};
+
 	cpus {
 		enable-method = "allwinner,sun6i-a31";
 		#address-cells = <1>;