kbuild: use GCOV_PROFILE and KCSAN_SANITIZE in scripts/Makefile.modfinal

Instead of filtering out the GCOV and KCSAN flags, let's set GCOV_PROFILE
and KCSAN_SANITIZE to 'n', as in other Makefiles.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Roberto Sassu <roberto.sassu@huawei.com>