Samsung SoC drivers changes for v5.16

1. Convert Exynos ChipID and ASV driver to a module and make it a
   default, instead of selected. The driver is not essential, so it
   could be disabled, if needed.
2. Add support for Exynos850 and Exynos Auto v9 to Exynos ChipID and ASV
   driver.
3. Get rid of HAVE_S3C_RTC because it was adding just another layer
   instead of direct dependencies.
4. Minor cleanups.