netxen: fix compile waring "label ‘set_32_bit_mask’ defined but not used" on IA64 platform

When compile the latest kernel on IA64 platform,I got a warning:
drivers/net/netxen/netxen_nic_main.c:203: warning: label ‘set_32_bit_mask’ 
defined but not used

We do not need label ‘set_32_bit_mask’  on IA64 platform,So move it to #else.

Signed-off-by: Yang Hongyang <yanghy@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>