sata_mv: platform driver allocs dma without create

When the sata_mv driver is used as a platform driver,
mv_create_dma_pools() is never called so it fails when trying
to alloc in mv_pool_start().

Signed-off-by: Byron Bradley <byron.bbradley@gmail.com>
Acked-by: Mark Lord <mlord@pobox.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>