dragonboard-820c: switch to packagegroup-firmware-dragonboard820c
dragonboard-820c: switch to packagegroup-firmware-dragonboard820c

Use packagegroup instead of referencing all firmware files in the machine conf file.

Signed-off-by: Dmitry Baryshkov <2dcd7ecf02101ef1dca344c0511f3ffb180907c2@linaro.org>

ndechesne/meta-qcom,ndechesne/meta-qcom,ndechesne/meta-qcom