dts: st: use dma defines to describe sai dma configs

[mariopaja]

Use DMA defines to describe SAI DMA configuration on STM32U5xx & STM32H5xx series
Although the DMA defines are not used to configure the SAI DMA, they give an overview over its configuration

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[evgeniy-paltsev]

the DMA defines are not used to configure the SAI DMA, they give an overview over its configuration

Nitpick - it worth to at least mention it in dts/bindings/i2s/st,stm32-sai.yaml (i.e. in dmas property description)

Although changing most of the dma configuration doesn't make sense for SAI, changing of STM32_DMA_PRIORITY_HIGH to other priority looks legit. So, as we don't support it, let's add explicit mention of that.

[mariopaja]

Hi @evgeniy-paltsev

Although changing most of the dma configuration doesn't make sense for SAI, changing of STM32_DMA_PRIORITY_HIGH to other priority looks legit.

Lets leave this as it is. I will write it down and open another PR for that 😃