ueventd: don't make /dev/DspBridge world-writable
init: change UART owner on boot

It appears that this improves the stability of the mobile signal
with no, or at least reduced, signal losses.
libcamera: replace continuous auto focus mode with infity focus mode

The continuous pictures focus mode is not actually supported. It was used
to allow taking pictures without having to wait for the focus. Use the
inifity focus mode instead and send FOCUS_MODE_AUTO to the sensor.