[IA64] generalize attribute of fsyscall_gtod_data

In an ordinary way,

> } __attribute__ ((aligned (L1_CACHE_BYTES)));

should be

> } ____cacheline_aligned;

to save some bytes on an uni-processor.

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