[HELP] Use cases for different sleep/delay functions

### Description

I am hoping to get some clarification on when it is appropriate to use each of the sleep/delay functions provided in NuttX.
- `up_delay`, `up_udelay` and `up_mdelay`
- `nxsig_sleep`, `nxsig_usleep`

If my understanding is correct, the `up_xdelay` functions are blocking and won't release the task during long blocks whereas the `nxsig_sleep` functions will release control so other tasks can run. I guess I am struggling to find a situation in which `up_delay` or `up_mdelay` should be used instead of `nxsig_usleep` in arch peripheral drivers. Are there side effects of `nxsig_` sleeps that I am missing?

Background for why I am asking this question: The STM32 ethernet drivers use both `nxsig_usleep` and `up_udelay`/`up_mdelay`. In one of our H7 applications, the blocking delays (`up_mdelay`) in `stm32_phyinit` has caused issues. While I work on adding STM32H5 peripheral drivers, I want to make sure I am using the correct functions for sleep/delays.

### Verification

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