Fix: mspm0: Remove a couple asserts

[ALTracer]

• Both assert conditions are true due to all respective calls in target_flash.c being flash->write(..., flash->writesize) (that's 8 bytes) or flash->erase(..., flash->blocksize) (that's 1024 byte blocks)
• This also should restore CI to passing status (for swlink/bluepill which overflow first)
• Not touching any other refactoring opportunities in here for now (like mixed usage of DEBUG_INFO/TARGET and string deduplication for calloc failed for... or new mass_erase).

See #1900 for additional explanations.

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• It builds as BMDA (see Building the BMDA)
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Closing issues

[dragonmux]

LGTM, merging. Thank you for the contribution!