[IA64] smp.c coding style fix

Fix indenting of switch statement to follow CodingStyle, and
pull out handling of call_data into an inlined function.

I confirmed that applying this fix doesn't affect assembled code.

Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>