dmaengine: at_hdmac: Substitute kzalloc with kmalloc

All members of the structure are initialized below in the function,
there is no need to use kzalloc.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Link: https://lore.kernel.org/r/20200123140237.125799-1-tudor.ambarus@microchip.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>