MFC r316777 (by cem)

dummynet: Use strlcpy to appease static checkers

Some dummynet modules used strcpy() to copy from a larger buffer
(dn_aqm->name) to a smaller buffer (dn_extra_parms->name). It happens that
the lengths of the strings in the dn_aqm buffers were always hardcoded to be
smaller than the dn_extra_parms buffer ("CODEL", "PIE").

Use strlcpy() instead, to appease static checkers. No functional change.

Reported by: Coverity
CIDs: 1356163, 1356165
Sponsored by: Dell EMC Isilon