meta-*: bump layers/bsp/meta-st-stm32mp from 74cfa68 to 8b449a5

Bumps [layers/bsp/meta-st-stm32mp](https://github.com/STMicroelectronics/meta-st-stm32mp) from `74cfa68` to `8b449a5`.
- [Release notes](https://github.com/STMicroelectronics/meta-st-stm32mp/releases)
- [Commits](STMicroelectronics/meta-st-stm32mp@74cfa68...8b449a5)

---
updated-dependencies:
- dependency-name: layers/bsp/meta-st-stm32mp
  dependency-version: 8b449a5ffe02a4622a1d404ede53ea9a5e6303d6
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]