ARM: imx: convert to common runtime ioremap hook

Convert i.MX platforms to use the common run-time ioremap hook instead of
the imx specific hook.

Also, move addr_in_module out of io.h.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Cc: Sascha Hauer <kernel@pengutronix.de>