[PATCH v3] pinctrl: elaborate a bit on arrangements in doc

[Stephen Warren]

On 07/21/2013 10:49 AM, Linus Walleij wrote:
> This elaborates a bit on the pin control and pin muxing
> logic vs GPIO arangements in the hardware.
> 
> Inspired by some drawings in a mail from Christian Ruppert.
> Both arrangements are confirmed to exist in practice.

Reviewed-by: Stephen Warren <swarren at nvidia.com>