lsblk: check number of used columns

lsblk: check number of used columns

The current code does not check size of the columns[] array when add
the next on command line specified column. We check the array size for
"-o <columns>" but not for another options.

Old version:

   $ for x in $(seq 0 100); do echo "-t"; done | xargs lsblk
   xargs: lsblk: terminated by signal 11

new version:

  $ for x in $(seq 0 100); do echo "-t"; done | xargs lsblk
  lsblk: too many columns specified, the limit is 83 columns.

Signed-off-by: Karel Zak <kzak@redhat.com>