busybox: nslookup_lede: fix compatibility with v1.25

busybox: nslookup_lede: fix compatibility with v1.25

The ":*" optstring syntax was only recently introduced with BusyBox v1.26,
older versions need a corresponding hint in the "opt_complementary" variable
to denote flag values that should be stored as llist entries.

Add the required opt_complementary entry to fix random SIGBUS, SIGILL or
SIGSEGV related crashes on BusyBox 1.25.x when attempting to use the "-q"
flag of the "nslookup_lede" applet.

Ref: https://forum.lede-project.org/t/nslookup-ipv6-in-lede-17-01-1

Signed-off-by: Jo-Philipp Wich <jo@mein.io>