dmaengine: mediatek: Use devm_platform_ioremap_resource() in mtk_cqdma_probe()

Simplify this function implementation a bit by using
a known wrapper function.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Link: https://lore.kernel.org/r/c7e3bbae-44fa-9019-18ee-c6cdfd7c2a14@web.de
Signed-off-by: Vinod Koul <vkoul@kernel.org>