Revert "config: strncpy_from_user && strnlen_user"

This reverts commit 26e8684fdcfc2f4bcb8e31d066f4a17060fcb9cd.
Revert "lib: strncpy_from_user && strnlen_user"

This reverts commit cd00ab0bd99272bc85c9e2a1dbf8f0a24e0b1de2.