[IA64] Clean-up McKinley Errata message

No need to print "McKinley Errata 9 workaround not needed; disabling it"
on every non-McKinley Itanium, which at this point is almost all of them.

Signed-off-by: Russ Anderson <(rja@sgi.com)>
Signed-off-by: Tony Luck <tony.luck@intel.com>