wireguard-tools: fix handling of multi-value config options
Config options like addresses and ip6prefix can be passed as either a
space-separated string or an array. Add a to_array() helper and use it
consistently for all multi-value options (addresses, ip6prefix,
allowed_ips).
Fixes: https://github.com/openwrt/openwrt/issues/22102 Fixes: 41bc454602f1 ("wireguard-tools: rewrite proto handler in ucode") Signed-off-by: Felix Fietkau <nbd@nbd.name>