[PATCH] i386: add smp_call_function_single

Continiung the series of small patches necessary for the perfmon subsystem,
here is a patch that adds support for the smp_call_function_single()
function for i386.  It exists for almost all other architectures but i386.
The perfmon subsystem needs it in one case to free some state on a
designated remote CPU.

Signed-off-by: Stephane Eranian <eranian@hpl.hp.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>