Merge tag 'u-boot-imx-main-20260727' of https://git.u-boot-project.org/u-boot/custodi...

CI: https://git.u-boot-project.org/u-boot/custodians/u-boot-imx/-/pipelines/749

- Support authenticating signed Mcore container image on i.MX9.
- Support booting CM70, CM71 and CM33 sync cores on i.MX9.
- Add i.MX SNVS RTC driver.
- Detect RAM sizes on Toradex smarc and aquila i.MX95 boards.
- Add support for the Librem5 devkit.
- Subtract half a cycle instead of three quarters of a cycle after DQS
  gating calibration on i.MX6.
- Several tqma6 improvements.
- Add product ID support for new Toradex boards.