pinctrl: Move am4372 and dra7 macros to the the SoC header files

The <dt-bindings/pinctrl/omap.h> header file defines a set of macros
for different SoCs families that falls under the OMAP sub-arch, that
allow to define the padconf register physical address instead of the
register offset from the padconf base.

But the am43xx and dra7xx SoCs families have their own pinctrl header
file so the DTS using these SoCs aren't able to use the AM4372_IOPAD()
and DRA7XX_CORE_IOPAD() macros since <dt-bindings/pinctrl/omap.h> is
not included.

Move the macros to the correct header files so can be used by the DTS.

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