x86: fix breakage of vSMP irq operations

25-rc* stopped working with CONFIG_X86_VSMP on vSMP machines.

Looks like the vsmp irq ops got accidentally removed during merge of x86_64
pvops in 2.6.25. -- commit 6abcd98f

 removed
vsmp irq ops.

Tested with both CONFIG_X86_VSMP and without CONFIG_X86_VSMP, on vSMP and non
vSMP x86_64 machines.

Please apply.

Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>