Replace the pair dma_alloc_coherent()+memset() with the new
dma_zalloc_coherent() added by Andrew Morton for kernel version 3.2
Signed-off-by: NAlexandre Bounine <alexandre.bounine@idt.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>