Extend boot partition size for RPi4

The boot partition is used to stored the Linux kernel, and should be enough to store at least two versions of it, for instance, to allow OSTree upgrades.

By default Apertis images uses 256 MB for this partition, but in RPi4 this pattern was not followed due to the presence of the firmware partition. Under this sceario OSTree tests might fail with the error:

Feb 22 05:19:24 apertis apertis-update-[1058]: Ostree upgrade failed: Installing kernel: regfile copy: No space left on device

In order to keep the same pattern as in other images extend this size moving all the other partitions.

Signed-off-by: Walter Lozano walter.lozano@collabora.com