SAM device file inconsistency for MCAN peripheral

[rleh]

The following lines do not describe disjoint device sets, because both match e.g. the same70q19b-an device, which causes errors in lbuild:

https://github.com/modm-io/modm-devices/blob/e093fe831fe17f1fec54bb31e038e499c22c2830/devices/sam/same70_s70_v70_v71.xml#L265-L266

[rleh]

I'll take a look at the device file generator...

[salkinium]

There are bugs in the merging code, I already broke my brain before trying to understand it.

[salkinium]

So there is a brute-force way to check the merge algorithm by adding the --check-merge flag to the generator. So ./sam_generator.py same7 sams7 samv7 --check-merge saves each individual tree, then merges, then for every device unmerges the tree and compares it to the seperately saved tree. Running that does not find any differences though.

[salkinium]

So that brute-force check is useless, it's clearly wrong, cos the single tree for the same70q19b-an is correct:

    <driver name="mcan" type="sam">
      <instance value="0"/>
      <instance value="1"/>
    </driver>

[salkinium]

I don't have a quick solution for this and we don't even have a functioning test for this to detect. I would suggest splitting the offending device file using the groups as a workaround that doesn't involve manual patching.

[salkinium]

Longer term, I would like to actually have a schema that validates such assumptions (no duplicate peripheral instances) so that we can actually test our data. At the moment that is all implicit and therefore terrible.