[IA64] wrong attribute of HUB chip written in uv_setup()

n_val should be assigned to n_val attribute of HUB chip.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>