[nrf fromlist] dts: nordic: Add wifi_spi label

Add wifi_spi label to nRF54h and nRF54l dts files to help
in shield overlay files

Upstream PR #: 85481

Signed-off-by: Bansidhar P.M <[email protected]>

Author: bama-nordic

boards/nordic/nrf54h20dk/nrf54h20dk_nrf54h20-common.dtsi

@@ -21,3 +21,6 @@
 	startup-time-us = <600000>;
 	mode = "crystal";
 };
+
+/* Get a node lablel for wi-fi spi to use in shield files */
+wifi_spi: &spi130 {};

boards/nordic/nrf54l15dk/nrf54l15dk_common.dtsi

@@ -98,3 +98,6 @@
 	pinctrl-1 = <&pwm20_sleep>;
 	pinctrl-names = "default", "sleep";
 };
+
+/* Get a node lablel for wi-fi spi to use in shield files */
+wifi_spi: &spi22 {};