motorola-smi: update kernel to 6.2 and boot with petitboot and devietree
Update linux-postmarketos-intel-medfield
kernel package to 6.2.7.
Let device-motorola-smi
depend on the new petitboot-motorola-smi
package and enable generation of grub.cfg instead of boot.img. This is needed, because the new kernel no longer supports SFI and boots only with devicetree.
The display is now fully functional with power on/off and brightness adjustment. And there is a basic battery driver. I updated the device wiki page accordingly.