[IA64-SGI] sn2 minor fixes and cleanups

General SN2 code cleanup:
 - Do not initialize global variables to zero
 - Use kzalloc instead of kmalloc+memset
 - Check kmalloc return values
 - Do not obfuscate spin lock calls
 - Remove some unused code
 - Various formatting cleanups

Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>