vt: simplify noncolor attributes in build_attr

All the attributes are bools, so do a simple shift instead of tests and
constants as bool is either 0 or 1.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200615074910.19267-28-jslaby@suse.cz


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>