uboot-envtools: mvebu: fix config for mainline u-boot

Mainline u-boot dynamically passes the mtd partitions via devicetree:
$ cat /proc/mtd
dev:    size   erasesize  name
mtd0: 003f0000 00001000 "firmware"
mtd1: 00010000 00001000 "u-boot-env"

Add support for this setup.

Signed-off-by: Andre Heider <a.heider@gmail.com>
(cherry picked from commit 60c9a27cbcc6ba00d75b4b592f507237dbfb460f)

package/boot/uboot-envtools/files/mvebu

@@ -20,7 +20,14 @@ cznic,turris-omnia)
 globalscale,espressobin|\
 globalscale,espressobin-emmc|\
 globalscale,espressobin-v7|\
-globalscale,espressobin-v7-emmc|\
+globalscale,espressobin-v7-emmc)
+	idx="$(find_mtd_index u-boot-env)"
+	if [ -n "$idx" ]; then
+		ubootenv_add_uci_config "/dev/mtd$idx" "0x0" "0x10000" "0x10000" "1"
+	else
+		ubootenv_add_uci_config "/dev/mtd0" "0x3f0000" "0x10000" "0x10000" "1"
+	fi
+	;;
 marvell,armada8040-mcbin)
 	ubootenv_add_uci_config "/dev/mtd0" "0x3f0000" "0x10000" "0x10000" "1"
 	;;