[maschull106]

Summary

• Add the STM32H5 SPI master, Rcc::setHsiDivider, the H5 ADC driver, and the advanced-timer update-event helpers (CR1.UDIS).
• Add the STM32H5 DMA and GPDMA drivers, then re-export the H5 DMA channel enums so colibry SPI DMA can use them.
• The GPDMA commits also edit the new ADC files, so ADC and DMA stay in this one review.

Test plan

• Generate and build an STM32H5 project that enables SPI master, ADC, and GPDMA.
• Confirm the H5 DMA channel enums are visible to a downstream colibry SPI DMA build.
• Leave f784d0a08 (software NSS and chunked TSIZE) for a follow-up after this merges. Do not open h5/spi_adc itself.