selftests/lkdtm: Remove dead config option

CONFIG_HARDENED_USERCOPY_FALLBACK config option has been removed in
commit 53944f17 ("mm: remove HARDENED_USERCOPY_FALLBACK"). Remove it
from the lkdtm selftest config.

Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Link: https://lore.kernel.org/r/20220121145154.1795447-1-usama.anjum@collabora.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>