added FP for AS3956-ATWx

Created by: cyber-murmel

Replace this line with your commit message! Please provide a description of your pull request

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All contributions to the kicad library must follow the KiCad library convention

Thanks for creating a pull request to contribute to the KiCad libraries! To speed up integration of your PR, please check the following items:

• Provide a URL to a datasheet for the footprint(s) you are contributing
  • https://ams.com/documents/20143/36005/AS3956_DS000546_7-00.pdf#page=98
• An example screenshot image is very helpful
  • 
• If there are matching symbol or 3D model pull requests, provide link(s) as appropriate
• Check the output of the Travis automated check scripts - fix any errors as required
• Give a reason behind any intentional library convention rule violation.