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:

modm-devices/devices/sam/same70_s70_v70_v71.xml

Lines 265 to 266 in e093fe8

	<instance device-series="e70|v70|v71" device-pin="n|q" device-flash="19|20" device-variant="b" value="1"/>
	<instance device-series="e70|v71" device-pin="n|q" device-flash="19|20|21" device-variant="a|b" value="1"/>

[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.