x86, trace: Remove __alloc_intr_gate()

Prepare to move set_intr_gate() into a macro by removing
__alloc_intr_gate().

The purpose is to avoid failing a kernel build after applying a
subsequent patch which changes set_intr_gate() into a macro.

Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Link: http://lkml.kernel.org/r/52716DB8.1080702@hds.com


Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>