ntpd: Fix segfault when same IP on multiple interfaces

Use the protype socket to obtain the IP address for an error message.
Using the resultant socket address, a NULL because create_interface()
had failed, results in SIGSEGV.

To reproduce this bug,

ifconfig bridge100 create
ifconfig bridge100 10.10.10.10/24
ifconfig bridge101 create
ifconfig bridge101 10.10.10.10/24
ntpd -n

PR: 291119

(cherry picked from commit ac1f48b4a7be104d222dea60f1da946fcb345fb1)