hardening: drop obsolete UBSAN_SANITIZE_ALL from config fragment

hardening: drop obsolete UBSAN_SANITIZE_ALL from config fragment

Commit 7a628f818499 ("ubsan: Remove CONFIG_UBSAN_SANITIZE_ALL") removes the
config UBSAN_SANITIZE_ALL, but one reference to that config is left in the
hardening.config fragment.

Drop this reference in hardening.config fragment.

Note that CONFIG_UBSAN is still enabled in the hardening.config fragment,
so the functionality when using this fragment remains the same.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Link: https://lore.kernel.org/r/20240208091045.9219-2-lukas.bulwahn@gmail.com
Signed-off-by: Kees Cook <keescook@chromium.org>