nanocoap_sock: add support for IPv4

[benpicco]

Contribution description

NanoCOAP is already agnostic towards the IP version, but there is one part where the code checks if the destination address is link-local, to see if an interface id is needed.
Since there are no link-local addresses with IPv4, we can simply not do that in the v4 only case.

Testing procedure

Build an LWIP IPv4 application with the nanocoap_vfs module (and default shell commands)

2024-03-17 17:42:20,985 # > ifconfig
2024-03-17 17:42:20,990 # Iface ET0 HWaddr: 7c:df:a1:02:ec:d4 Link: up State: up
2024-03-17 17:42:20,991 #         Link type: wireless
2024-03-17 17:42:20,998 #         inet addr: 10.53.4.195 mask: 255.255.0.0 gw: 10.53.0.1

2024-03-17 17:42:22,763 # > ncget coap://134.102.218.18/
2024-03-17 17:42:22,791 # /test
2024-03-17 17:42:22,792 # /validate
2024-03-17 17:42:22,814 # /hello
2024-03-17 17:42:22,843 # /blåbærsyltetøy
2024-03-17 17:42:22,843 # /sink
2024-03-17 17:42:22,867 # /separate
2024-03-17 17:42:22,867 # /large
2024-03-17 17:42:22,916 # /secret
2024-03-17 17:42:22,960 # /broken
2024-03-17 17:42:22,960 # /weird33
2024-03-17 17:42:22,961 # /weird44
2024-03-17 17:42:22,990 # /weird55
2024-03-17 17:42:22,991 # /weird333
2024-03-17 17:42:23,023 # /weird3333
2024-03-17 17:42:23,023 # /weird33333
2024-03-17 17:42:23,079 # /123412341234123412341234
2024-03-17 17:42:23,107 # /location-query
2024-03-17 17:42:23,136 # /create1
2024-03-17 17:42:23,137 # /large-update
2024-03-17 17:42:23,161 # /large-create
2024-03-17 17:42:23,161 # /query
2024-03-17 17:42:23,190 # /seg1
2024-03-17 17:42:23,191 # /path
2024-03-17 17:42:23,191 # /location1
2024-03-17 17:42:23,214 # /multi-format
2024-03-17 17:42:23,214 # /3
2024-03-17 17:42:23,239 # /4
2024-03-17 17:42:23,239 # /5

Issues/PRs references

[riot-ci]

Murdock results

✔️ PASSED

408218f nanocoap_sock: support build with IPv4

Success	Failures	Total	Runtime
10009	0	10009	07m:55s

Artifacts