ata: pdc_adma: Remove call to memset after dmam_alloc_coherent

In commit af7ddd8a
("Merge tag 'dma-mapping-4.21' of git://git.infradead.org/users/hch/dma-mapping"),
dmam_alloc_coherent has already zeroed the memory.
So memset is not needed.
Signed-off-by: Fuqian Huang <huangfq.daxian@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/ata/pdc_adma.c

@@ -550,7 +550,6 @@ static int adma_port_start(struct ata_port *ap)
 						(u32)pp->pkt_dma);
 		return -ENOMEM;
 	}
-	memset(pp->pkt, 0, ADMA_PKT_BYTES);
 	ap->private_data = pp;
 	adma_reinit_engine(ap);
 	return 0;