PM / Hibernate: Shift remaining code from swsusp.c to hibernate.c

Shift the remaining declaration of the variable in_suspend and the
function swsusp_show_speed from swsusp.c to hibernate.c, and delete
swsusp.c.

Signed-off-by: Nigel Cunningham <nigel@tuxonice.net>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>