Upstream commit message:

[PATCH 2/3] WPS UPnP: Fix event message generation using a long URL path

More than about 700 character URL ended up overflowing the wpabuf used
for building the event notification and this resulted in the wpabuf
buffer overflow checks terminating the hostapd process. Fix this by
allocating the buffer to be large enough to contain the full URL path.
However, since that around 700 character limit has been the practical
limit for more than ten years, start explicitly enforcing that as the
limit or the callback URLs since any longer ones had not worked before
and there is no need to enable them now either.

Obtained from: https://w1.fi/security/2020-1/\
0002-WPS-UPnP-Fix-event-message-generation-using-a-long-U.patch
Security: VU#339275 and CVE-2020-12695