ipq40xx: dts: fix dtc warnings for MikroTik hAP ac3 LTE6

ipq40xx: dts: fix dtc warnings for MikroTik hAP ac3 LTE6

Correct the mtd partition reg property size to fix the following
dtc warnings:

qcom-ipq4019-hap-ac3-lte6-kit.dts:202.5-25: Warning (reg_format): /soc/spi@78b5000/flash@0/partitions/partition@0:reg: property has invalid length (8 bytes) (#address-cells == 2, #size-cells == 1)
qcom-ipq4019-hap-ac3-lte6-kit.dts:209.5-29: Warning (reg_format): /soc/spi@78b5000/flash@0/partitions/partition@80000:reg: property has invalid length (8 bytes) (#address-cells == 2, #size-cells == 1)
qcom-ipq4019-hap-ac3-lte6-kit.dts:226.5-31: Warning (reg_format): /soc/spi@78b5000/flash@0/partitions/partition@110000:reg: property has invalid length (8 bytes) (#address-cells == 2, #size-cells == 1)

Signed-off-by: Shiji Yang <yangshiji66@outlook.com>
Link: https://github.com/openwrt/openwrt/pull/18725
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>