kernel/watchdog: introduce arch_touch_nmi_watchdog()

kernel/watchdog: introduce arch_touch_nmi_watchdog()

For architectures that define HAVE_NMI_WATCHDOG, instead of having them
provide the complete touch_nmi_watchdog() function, just have them
provide arch_touch_nmi_watchdog().

This gives the generic code more flexibility in implementing this
function, and arch implementations don't miss out on touching the
softlockup watchdog or other generic details.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Nicholas Piggin <[email protected]>
Reviewed-by: Don Zickus <[email protected]>
Reviewed-by: Babu Moger <[email protected]>
Tested-by: Babu Moger <[email protected]>	[sparc]
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Michael Ellerman <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>