mx6q: define GPIO macros for translating between ordinals and port:index

mx6q: define GPIO macros for translating between ordinals and port:index

The interface to the mxc_gpio driver uses integer (ordinal) values to
refer to all GPIOs on the i.MX processors. The registers themselves
and much of the i.MX documentation are banked in groups of 32, and these
macros allow the use of the port:index numbering for clarity.

GPIO_NUMBER() converts to ordinal value from port:index
GPIO_PORT() returns the port of an ordinal value
GPIO_INDEX() returns the index or offset of the ordinal.

Discussion on the mailing list at
	http://lists.denx.de/pipermail/u-boot/2012-January/116927.html

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>
Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>