dmaengine: zx: Use devm_platform_ioremap_resource() in zx_dma_probe()

Simplify this function implementation by using a known wrapper function.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Acked-by: Shawn Guo <shawnguo@kernel.org>
Link: https://lore.kernel.org/r/85de79fa-1ca5-a1e5-0296-9e8a2066f134@web.de
Signed-off-by: Vinod Koul <vkoul@kernel.org>