Genwqe uses dma_alloc_coherent and depends on zero initialized memory. On
one occasion it ueses an explicit memset on others it uses un-initialized
memory.

This bug was covered because some archs actually return zero initialized
memory when using dma_alloc_coherent but this is by no means guaranteed.
Simply switch to dma_zalloc_coherent.
Signed-off-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: NFrank Haverkamp <haver@linux.vnet.ibm.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>