Increase maximal Mchan DMA transfer sizes from 64KiB to 128KiB

[Victor-Jung]

This PR increases the maximal transfer sizes from 64KiB to 128KiB for the Mchan DMA (L1 <-> L2) of the Siracusa platform.

In previous versions of Mchan, the transfer length was encoded on 16 bits; since version 7, we can use 17 bits.

Added

• Asserting the size of the transfer when generating the struct to configure DMA transfers to raise an error early if a transfer is invalid.
• largeFloadAdd test in the CI. It performs a DMA transfer of size higher than 2^16.

Changed

• The field of the data struct carrying the DMA transfer length is now a uint32 instead of uint16.

PR Merge Checklist

1. The PR is rebased on the latest devel commit and pointing to devel.
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4. The CHANGELOG.md file has been updated.
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