linux: replace u-boot,env with nvmem,layout

The former is deprecated in favor of nvmem-layout. In preparation for
eventual removal from the kernel, do so here.

Signed-off-by: Rosen Penev <rosenp@gmail.com>
Link: https://github.com/openwrt/openwrt/pull/16097
Signed-off-by: Robert Marko <robimarko@gmail.com>

target/linux/mediatek/dts/mt7981b-glinet-gl-mt2500.dts

@@ -163,6 +163,7 @@
 			partitions {
 				block-partition-u-boot-env {
 					partname = "u-boot-env";
+
 					nvmem-layout {
 						compatible = "u-boot,env";
 					};

target/linux/mediatek/files-6.6/arch/arm64/boot/dts/mediatek/mt7988a-bananapi-bpi-r4-emmc.dtso

@@ -40,6 +40,7 @@
 					partitions {
 						block-partition-env {
 							partname = "ubootenv";
+
 							nvmem-layout {
 								compatible = "u-boot,env";
 							};

target/linux/mediatek/files-6.6/arch/arm64/boot/dts/mediatek/mt7988a-bananapi-bpi-r4-sd.dtso

@@ -38,6 +38,7 @@
 					partitions {
 						block-partition-env {
 							partname = "ubootenv";
+
 							nvmem-layout {
 								compatible = "u-boot,env";
 							};