SOFTWARE_SUSPEND: fix a typo in the dependencies

This patch fixes a typo in the dependencies of SOFTWARE_SUSPEND.

This patch is based on a report by
Jean-Luc Leger <reiga@dspnet.fr.eu.org>.

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Acked-by: Pavel Machek <pavel@ucw.cz>