[PATCH] qe_ic: Do a sync when masking interrupts.

[Liu Dave-r63238]

> > > Segher Boessenkool wrote:
> > > > If a sync after an MMIO write is enough, then (in almost all
> > > > cases) so is an eieio.
> > > 
> > > In this case, the spurious interrupts still happen with 
> eieio, but 
> > > not with sync.
> > 
> > eieio on e300 core is just a no-op.
> 
> It's not sent to the bus on non-cahed storage (like the PCI 
> bridge ?) That's pretty bad ... there is quite a bit of code 
> that assumes that eieio's will prevent write combining...

Due to the LSU, the e300 cored doesn't reorder non-cached
stroage, and doesn't implementation of write commbining.
So, actually its behavior likes eieio.

-Dave