libifconfig: Add missing symbols to map

Regenerate the list of generated symbols for libifconfig:

grep -hr ^ifconfig_sfp_ /usr/obj/usr/src/amd64.amd64/lib/libifconfig \
| sed 's/(.*/;/' | sort -u

Spotted by build failures caused by a missing symbol while working on
upgrading libifconfig from internal to private.

Reviewed by: markj
Differential Revision: https://reviews.freebsd.org/D28927