rtc-cmos: display HPET emulation mode

rtc-cmos: display HPET emulation mode

For the "cmos" RTC, have /proc/driver/rtc say whether HPET based IRQ
emulation is in effect.  Given the problems we've had with this particular
hardware maldesign (and the fact that most BIOS code seems not to provide
the IRQ routing needed to use the saner HPET modes), this should help
troubleshooting.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>