[IA64] s/scalibility/scalability/

Previous spelling patch from Simon Arlott broke one spot that
didn't need fixing (reported by Simon within 35 minutes of the
patch ... but not until after I'd applied to GIT and pushed :-(

Signed-off-by: Tony Luck <tony.luck@intel.com>

arch/ia64/kernel/time.c

@@ -216,7 +216,7 @@ ia64_init_itm (void)
 #ifdef CONFIG_SMP
 		/* On IA64 in an SMP configuration ITCs are never accurately synchronized.
 		 * Jitter compensation requires a cmpxchg which may limit
-		 * the scalibility of the syscalls for retrieving time.
+		 * the scalability of the syscalls for retrieving time.
 		 * The ITC synchronization is usually successful to within a few
 		 * ITC ticks but this is not a sure thing. If you need to improve
 		 * timer performance in SMP situations then boot the kernel with the