tty: vt, use proper type for default colors

Every user of default_red, default_grn, and default_blu treats them as
unsigned char. So make it really unsigned char.

And indent the initializers and module_param properly.

This saves ~ 100 bytes of data.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>