mvebu: move upstreamed DTS files (ESPRESSObin) to files-5.4

Since kernel 5.5-rc1 [1], there are upstreamed DTS files related to ESPRESSObin
variants. Move these to files-5.4.

This helps if you want to use a newer kernel version than used
in OpenWrt 21.02 (= LTS kernel 5.4), you would end up with duplicate files
(one outdated, one up to date from newer Linux versions).

Fixes:
Error: arch/arm64/boot/dts/marvell/armada-3720-espressobin-v7.dts:19.1-7:
Label or path ports not found
FATAL ERROR: Syntax error parsing input tree

[1] https://github.com/torvalds/linux/commit/447b8789359f9a5e6567c4044d18abaa7de68930

Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>
(cherry picked from commit 7be8ab4f7b582924bca6594103735d888989d804)
Signed-off-by: Josef Schlehofer <pepe.schlehofer@gmail.com>
[reword commit subject and commit description]

diff --git a/target/linux/mvebu/files/arch/arm64/boot/dts/marvell/armada-3720-espressobin-emmc.dts b/target/linux/mvebu/files-5.4/arch/arm64/boot/dts/marvell/armada-3720-espressobin-emmc.dts
similarity index 100%
rename from target/linux/mvebu/files/arch/arm64/boot/dts/marvell/armada-3720-espressobin-emmc.dts
rename to target/linux/mvebu/files-5.4/arch/arm64/boot/dts/marvell/armada-3720-espressobin-emmc.dts

diff --git a/target/linux/mvebu/files/arch/arm64/boot/dts/marvell/armada-3720-espressobin-v7-emmc.dts b/target/linux/mvebu/files-5.4/arch/arm64/boot/dts/marvell/armada-3720-espressobin-v7-emmc.dts
similarity index 100%
rename from target/linux/mvebu/files/arch/arm64/boot/dts/marvell/armada-3720-espressobin-v7-emmc.dts
rename to target/linux/mvebu/files-5.4/arch/arm64/boot/dts/marvell/armada-3720-espressobin-v7-emmc.dts

diff --git a/target/linux/mvebu/files/arch/arm64/boot/dts/marvell/armada-3720-espressobin-v7.dts b/target/linux/mvebu/files-5.4/arch/arm64/boot/dts/marvell/armada-3720-espressobin-v7.dts
similarity index 100%
rename from target/linux/mvebu/files/arch/arm64/boot/dts/marvell/armada-3720-espressobin-v7.dts
rename to target/linux/mvebu/files-5.4/arch/arm64/boot/dts/marvell/armada-3720-espressobin-v7.dts