ARM: dts: imxrt1020-evk-u-boot: make gpt1 present for SPL

Timer needs to be already enabled in spl, so let's add its node to spl dtb.

Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>

arch/arm/dts/imxrt1020-evk-u-boot.dtsi

@@ -10,6 +10,10 @@
 	};
 };
 
+&gpt1 {
+	u-boot,dm-spl;
+};
+
 &lpuart1 { /* console */
 	u-boot,dm-spl;
 };