ARM: dts: Change IOPAD macro's for OMAP4/5

The OMAP4/5 TRMs primarily list address offsets from the padconf
physical address (which is not driver base address) and not
always the absolute physical address for padconf registers like
some other OMAP TRMs. So create a new macro to use this offset
and to avoid confusion between different OMAP parts.

For more information, see the tables in TRM for named something like
"Device Core Control Module Pad Configuration Register Fields"
and "Device Wake-Up Control Module Pad Configuration Register Fields"

Note that we now also have to update cm-t54 for the fixed up
offsets.

Signed-off-by: Joachim Eastwood <manabian@gmail.com>
[tony@atomide.com: updated comments, updated cm-t54]
Signed-off-by: Tony Lindgren <tony@atomide.com>