Remove an incorrect debug printf.
Quiesce warning -Wmissing-variable-declarations from buildworld, which is
slightly unnerving.

In file included from ioctl.c:48:
/var/tmp/home/sbruno/bsd/head/tmp/usr/include/dev/lmc/if_lmc.h:939:13:
warning: no previous extern declaration for non-static variable 'ssi_cables'
[-Wmissing-variable-declarations]
const char *ssi_cables[] =