jh7110.dtsi: fix wrong offset for fwcfg, and make whole QSPI be available
requested to merge github/fork/strlcat/JH7110_VisionFive2_devel_PRfwcfg_offs into JH7110_VisionFive2_devel
Created by: strlcat
Fix typo in fwcfg offset (0xF00000 -> 0xF0000), so Linux uboot-tools can access fwcfg block to modify boot configuration from userspace.
While we're at it, let's repartition QSPI into more handy style, by applying table from https://doc-en.rvspace.org/VisionFive2/Boot_UG/JH7110_SDK/boot_address_allocation.html.