ata:sata_qstor: 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/sata_qstor.c

@@ -477,7 +477,6 @@ static int qs_port_start(struct ata_port *ap)
 				      GFP_KERNEL);
 	if (!pp->pkt)
 		return -ENOMEM;
-	memset(pp->pkt, 0, QS_PKT_BYTES);
 	ap->private_data = pp;
 
 	qs_enter_reg_mode(ap);