x86: correct link to HPET timer specification

Impact: update documentation / help text

Original link is dead.

Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index ac22bb7..19f0d97 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -482,7 +482,7 @@
          The HPET provides a stable time base on SMP
          systems, unlike the TSC, but it is more expensive to access,
          as it is off-chip.  You can find the HPET spec at
-         <http://www.intel.com/hardwaredesign/hpetspec.htm>.
+         <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
 
          You can safely choose Y here.  However, HPET will only be
          activated if the platform and the BIOS support this feature.