pata_imx: Use devm_ioremap_resource() to simplify code

Using devm_ioremap_resource() can lead to code simplication, as we don't need
to explicitily check for error returned by platform_get_resource().

Also, no need to print an error message when devm_ioremap_resource() fails,
as the OOM code code will shout loudly on such condition.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Tejun Heo <tj@kernel.org>