fix read-only peripheral

[kossnikita]

fix !19

[PhilippHaefele]

After a quick look into SVD specifications (https://www.keil.com/pack/doc/CMSIS/SVD/html/elem_registers.html & https://www.keil.com/pack/doc/CMSIS/SVD/html/elem_special.html#registerPropertiesGroup_gr), I suspect that access rights are not writable by default and there's only an inheritance model.

So changing the default here mist likely will not fix it in an appropriate way.

I didn't look into code to be precise on this, so not really sure

[kossnikita]

UPD: Good catch! Please give me feedback on the new solution

[kossnikita]

I suspect that access rights are not writable by default

I can't find any informtion about this. Therefore, I believe that it should have read-write based on my reading of svd files, in which often access is not specified at all, although read-write is supposed