[IA64] Convert to generic timekeeping/clocksource

This is a merge of Peter Keilty's initial patch (which was
revived by Bob Picco) for this with Hidetoshi Seto's fixes
and scaling improvements.

Acked-by: Bob Picco <bob.picco@hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index 616c96e..36c7b96 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -62,7 +62,11 @@
 	bool
 	default y
 
-config TIME_INTERPOLATION
+config GENERIC_TIME
+	bool
+	default y
+
+config GENERIC_TIME_VSYSCALL
 	bool
 	default y