mvebu: fix partition node dtc warnings for Synology DS213j

mvebu: fix partition node dtc warnings for Synology DS213j

Add missing #address-cells and #size-cells to fix the
following dtc warnings:

armada-370-synology-ds213j.dts:288.5-35: Warning (reg_format): /soc/spi@10600/flash@0/partitions/partition@0:reg: property has invalid length (8 bytes) (#address-cells == 2, #size-cells == 1)
armada-370-synology-ds213j.dts:294.5-35: Warning (reg_format): /soc/spi@10600/flash@0/partitions/partition@c0000:reg: property has invalid length (8 bytes) (#address-cells == 2, #size-cells == 1)
armada-370-synology-ds213j.dts:299.5-35: Warning (reg_format): /soc/spi@10600/flash@0/partitions/partition@100000:reg: property has invalid length (8 bytes) (#address-cells == 2, #size-cells == 1)
armada-370-synology-ds213j.dts:304.5-35: Warning (reg_format): /soc/spi@10600/flash@0/partitions/partition@110000:reg: property has invalid length (8 bytes) (#address-cells == 2, #size-cells == 1)
armada-370-synology-ds213j.dts:308.5-35: Warning (reg_format): /soc/spi@10600/flash@0/partitions/partition@7d0000:reg: property has invalid length (8 bytes) (#address-cells == 2, #size-cells == 1)
armada-370-synology-ds213j.dts:327.5-35: Warning (reg_format): /soc/spi@10600/flash@0/partitions/partition@7e0000:reg: property has invalid length (8 bytes) (#address-cells == 2, #size-cells == 1)

Signed-off-by: Shiji Yang <[email protected]>
Link: https://github.com/openwrt/openwrt/pull/18242
Signed-off-by: Hauke Mehrtens <[email protected]>