ivtv: Fix PCI DMA direction

The ivtv stream buffers may be for receive or for send but the attached
sg handle is always destined cpu->device.  We flush it correctly but the
allocation is wrongly done with the same type as the buffers.

See bug: http://bugzilla.kernel.org/show_bug.cgi?id=13385

(Note this doesn't close the bug - it fixes the ivtv part and in turn
the logging next shows up some rather alarming DMA sg list warnings in
libata)

Signed-off-by: Alan Cox <alan@linux.intel.com>
Acked-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>