clocksource: Add new feature flag CLOCK_SOURCE_SUSPEND_NONSTOP

Some x86 processors have a TSC clocksource, which continues to run
even when system is suspended. Also most OMAP platforms have a
32 KHz timer which has similar capability. Add a feature flag so that
it could be utilized.
Signed-off-by: NFeng Tang <feng.tang@intel.com>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

include/linux/clocksource.h

@@ -206,6 +206,7 @@ struct clocksource {
 #define CLOCK_SOURCE_WATCHDOG			0x10
 #define CLOCK_SOURCE_VALID_FOR_HRES		0x20
 #define CLOCK_SOURCE_UNSTABLE			0x40
+#define CLOCK_SOURCE_SUSPEND_NONSTOP		0x80
 
 /* simplify initialization of mask field */
 #define CLOCKSOURCE_MASK(bits) (cycle_t)((bits) < 64 ? ((1ULL<<(bits))-1) : -1)