[POWERPC] pmu_sys_suspended is only defined for PPC32

thus we get a link error on ppc64 with CONFIG_PM=y.  This fixes it.
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

include/linux/pmu.h

@@ -226,7 +226,7 @@ extern unsigned int pmu_power_flags;
 extern void pmu_backlight_init(void);
 
 /* some code needs to know if the PMU was suspended for hibernation */
-#ifdef CONFIG_PM
+#if defined(CONFIG_PM) && defined(CONFIG_PPC32)
 extern int pmu_sys_suspended;
 #else
 /* if power management is not configured it can't be suspended */