drivers: dma: paxdma: Sync payload as separate packet

Sync packet is always CARD to HOST and if it's combined with HOST
to CARD transfers in one single RM header packet, it's not allowed
due to RM implementation constraints. RM implementation allows same
type of data transfer direction in all the BD's populated under one
header BD.

Signed-off-by: Raveendra Padasalagi <raveendra.padasalagi@broadcom.com>