rtc: imxdi: use devm_platform_ioremap_resource() to simplify code

Use the new helper devm_platform_ioremap_resource() which wraps the
platform_get_resource() and devm_ioremap_resource() together, to
simplify the code.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Link: https://lore.kernel.org/r/20190717081411.30622-1-Anson.Huang@nxp.com


Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>