Pull up following revision(s) (requested by ozaki-r in ticket #1960):

sys/netinet6/frag6.c: revision 1.78

frag6: fix calculation of fragment length

Because of the miscalculation, 32 bytes fragmented IPv6 packets
have been wrongly dropped.

See https://mail-index.netbsd.org/tech-net/2024/04/14/msg008741.html
for more details.

Patch from Yasuyuki KOZAKAI (with minor tweaks)

(martin)