Fix EFM8BB10F8G-A-QFN20 default FP

[chschlue]

see KiCad/kicad-footprints#1989
depends on KiCad/kicad-footprints#2139

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[cpresser]

While you are at it, can you please fix the pin-name-position-offset?
How about also changing the GND pins to be stacked. That won't break existing schematics, just make them look ugly.

[chschlue]

Done.

[chschlue]

@cpresser FP changes have been merged.