19628: Fix periph clk r=aabadie a=Enoch247
### Contribution description
This fixes some minor doc and argument type errors. See commit messages for details.
### Testing procedure
It compiles without errors for me.
### Issues/PRs references
None known
19637: sys/usb/usbus_msc: fix typo in C expression r=aabadie a=maribu
### Contribution description
Rather than setting the correct blk_len, the code only wrote 1 and 0 into the three bytes due to the use of a logic and where a bitwise and should be used.
Co-authored-by: Joshua DeWeese <jdeweese@primecontrols.com>
Co-authored-by: Marian Buschsieweke <marian.buschsieweke@ovgu.de>