librem5-devkit.conf: set the operating mode to bluetooth EDR

Firmware vesion 2.0.0024 broke BLE so we need to disable dual bluetooth support

Signed-off-by: Angus Ainslie <angus@akkea.ca>
3 jobs for bt-dual-amber in 8 minutes and 10 seconds (queued for 21 minutes and 58 seconds)
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passed #350529
librem5
build:deb

00:02:40

 
  Test
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librem5
test:download:deb

00:02:23

passed #350531
librem5
test:download:pip

00:03:11