dmaengine: at_hdmac: Check return code of dma_async_device_register

dma_async_device_register() can fail, check the return code and display an
error.

Fixes: dc78baa2

 ("dmaengine: at_hdmac: new driver for the Atmel AHB DMA Controller")
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Cc: stable@vger.kernel.org
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Link: https://lore.kernel.org/r/20221025090306.297886-1-tudor.ambarus@microchip.com
Link: https://lore.kernel.org/r/20221025090306.297886-16-tudor.ambarus@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>