[OE-core] [RFC oe-core] mkcard: Add a script to parition and format an SD Card

[Jason Kridner]

>>>
>>> This script is BSP specific and shouldn't live in the OE-core layer.
>>
>> The only issue is this script is used from within the IMAGE_CMD_sdimg
>> code which lives in OE-core (meta/classes/image_types.
>
> classes shouldn't be calling external scripts
>

Is the right approach to add parameters to the IMAGE_CMD_sdimg class
such that it can be used generically to produce SD card images,
instead of trying to move this to meta-ti?  Should it perhaps be a bit
closer to what is being done by the Linaro image tools [1]?

[1] https://wiki.linaro.org/Source/ImageBuilding