linux-purism-librem5: sync kconfig

Following up on discussions on !5252 (merged)

With the latest kernel bump the config was updated based on the output of:

make ARCH="$_carch" CC="${CC:-gcc}" defconfig KBUILD_DEFCONFIG=librem5_defconfig

but there are other changes that pop up when running

pmbootstrap kconfig edit linux-purism-librem5

This commit updates the config so that future empty config edits don't generate any changes.

This is still pretty in sync with the Purism config, besides passing the kconfig check and disabling SELinux as that causes boot failures.