ARM: mx3: make ioremap quirk ready for multi-SoC kernels

To be able to compile e.g. i.MX31 and i.MX51 in a single kernel image
the ioremap quirk needs a runtime check.

While touching this code make the comment more understandable by adding
a sentence from the commit log that introduced it
(eadefeff ([ARM] MX3: Use ioremap wrapper to map SoC devices nonshared)).

As mach/io.h now uses cpu_is_ some header reshuffling in mach/hardware.h
was necessary. (mach/mx27.h and mach/mx31.h #include <linux/io.h> which
#includes <mach/io.h>. So mach/mxc.h which provides the cpu_is_ macros
needs to be included before mach/mx27.h and mach/mx31.h.)

LAKML-Reference: 1302464943-20721-5-git-send-email-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>