mfd: intel-lpss: Fix build error when !CONFIG_PM_SLEEP

Jim Davis reported the compilation error with a random configuration which
apparently has CONFIG_PM=y and CONFIG_PM_SLEEP=n. With that conditions we have
missed definition of INTEL_LPSS_SLEEP_PM_OPS macro. Add it here.
Reported-by: Jim Davis <jim.epost@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/intel-lpss.h

@@ -42,6 +42,8 @@ int intel_lpss_resume(struct device *dev);
 	.thaw = intel_lpss_resume,		\
 	.poweroff = intel_lpss_suspend,		\
 	.restore = intel_lpss_resume,
+#else
+#define INTEL_LPSS_SLEEP_PM_OPS
 #endif
 
 #define INTEL_LPSS_RUNTIME_PM_OPS		\