Char: cyclades, fix unused variable

drivers/tty/cyclades.c:1454:2: warning: Value stored to 'channel' is never read
	channel = info->line - card->first_line;
	^         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fix it by moving it to the appropriate debug section where it is used.

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