dts: nordic: nrf91xx: fix NS partition references

`sram0_ns_modem` and `sram0_ns_app` are child nodes of `sram0_ns`, not
`sram`. Addresses should be relative to the former, not the later.

Signed-off-by: Jordan Yates <[email protected]>

Author: JordanYates

dts/vendor/nordic/nrf91xx_partition.dtsi

@@ -116,12 +116,12 @@
 		#size-cells = <1>;
 		ranges = <0x0 0x16000 DT_SIZE_K(168)>;
 
-		sram0_ns_modem: sram@0 {
+		sram0_ns_modem: sram0_ns@0 {
 			/* Modem (shared) memory */
 			reg = <0x0 DT_SIZE_K(40)>;
 		};
 
-		sram0_ns_app: sram@a000 {
+		sram0_ns_app: sram0_ns@a000 {
 			/* Non-Secure application memory */
 			reg = <0xa000 DT_SIZE_K(128)>;
 		};