ARM: dts: omap3-evm-37xx: Use OMAP3_*_IOPAD pinmux macros

Use the pinmux IOPAD macros to define the register absolute physical
address instead of the offset from the padconf base address. This
makes the DTS easier to read since matches the addresses listed in
the Technical Reference Manual.

Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>