[IA64] move gcc_intrin.h from header-y to unifdef-y

When I submitted 0df29025

 to ad
an #ifdef __KERNEL__ to include/asm-ia64/gcc_intrin.h a few weeks
ago I neglected to move gcc_intrin.h from header-y to unifdef-y.
Thanks to David Woodhouse for pointing this out.

Signed-off-by: Doug Chapman <doug.chapman@hp.com>
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>