iop: genconfig: Remove config options set in targets already

Remove CONFIG_TARGET_MULTI_PROFILE=y and CONFIG_TARGET_PER_DEVICE_ROOTFS=y that were hardcoded in genconfig and genconfig_min. Since feeds/targets commit 295d1566 (treewide: Add MULTI_PROFILE and PER_DEVICE_ROOTFS config, 2021-08-05), the options are added in feeds/targets.

Also bring the unmaintainable copy-paste of genconfig that is genconfig_min in sync with genconfig with regards target-specific config options.