kernel: Create recommended configs file
We've started to have more and more "recommended" but not "required"
kernel configs (i.e. hardware-specific, etc). Instead of confusingly
requiring them or forcing them into defconfig files, split these out
into a single file that can be overridden on a per-product basis.
Additionally fixes a bug with the PSTORE config (which needed the
MISC_FILESYSTEMS config too), simplifies the prebuilt check, and
documents some missing target variables.
3 files changed