vt: selection, remove 2 local variables from set_selection_kernel

multiplier and mode are not actually needed:
* multiplier is used only in kmalloc_array, so use "use_unicode ? 4 : 1"
  directly
* mode is used only to assign a bool in this manner:
  if (cond)
    x = true;
  else
    x = false;
  So do "x = cond" directly.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219073951.16151-3-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>