[PATCH] IP27: Really set PCI64_ATTR_VIRTUAL, not PCI64_ATTR_PREC.

IOC3's homegrown DMA mapping functions that are used to optimize things
a little on IP27 set the wrong bit.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>