staging: unisys: correctly handle return value from queue_delayed_work()

commit f84bd626 upstream.

Properly handle the return value from queue_delayed_work() - it's a
bool, not an int, so using a less than comparison isn't appropriate.

This mistake was found by David Binderman <dcb314@hotmail.com>.

[arnd: the fix is from 4.4 but needed some minor fixup to adapt
 to context changes]

Signed-off-by: Benjamin Romer <benjamin.romer@unisys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>