power: supply: Add Apple Brick ID power supply type

power: supply: Add Apple Brick ID power supply type

Apple currently supports three very common USB chargers:
https://www.apple.com/power-adapters/

These chargers implement a proprietary Apple method for advertising
1A, 2.1A, and 2.4A at 5V called "Brick ID".
In addition, 3rd parties implement the same charging method in many
charging accessories that work with iOS devices.

Devices that have charger detection chips such as the Pericom PI3USB9281,
eg. Google Chromebook Pixel 2015, are capable of detecting
these chargers, so let's add a type to facilicate passing that info
up to userspace.

This adds a separate power supply type for Apple's proprietary
"Brick ID" charging method.

Signed-off-by: Benson Leung <bleung@chromium.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>