[ARM] 4272/1: Missing symbol h1940_pm_return fix

Added missing ifdefs, to make kernel linkable without the PM support.

Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>