arm64: dts: ls208xa: use defines for timer interrupts

Replace hard-coded interrupt parts (GIC, flags) with standard defines
for readability.  No changes in resulting DTBs.  The comment was saying
interrupt was active low, but the actual used value was active high, so
assume that the code, not the comment, is correct.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/fsl-ls208xa.dtsi

@@ -241,10 +241,10 @@ map0 {
 
 	timer: timer {
 		compatible = "arm,armv8-timer";
-		interrupts = <1 13 4>, /* Physical Secure PPI, active-low */
-			     <1 14 4>, /* Physical Non-Secure PPI, active-low */
-			     <1 11 4>, /* Virtual PPI, active-low */
-			     <1 10 4>; /* Hypervisor PPI, active-low */
+		interrupts = <GIC_PPI 13 IRQ_TYPE_LEVEL_HIGH>, /* Physical Secure PPI */
+			     <GIC_PPI 14 IRQ_TYPE_LEVEL_HIGH>, /* Physical Non-Secure PPI */
+			     <GIC_PPI 11 IRQ_TYPE_LEVEL_HIGH>, /* Virtual PPI */
+			     <GIC_PPI 10 IRQ_TYPE_LEVEL_HIGH>; /* Hypervisor PPI */
 	};
 
 	psci {