kbuild: clang: fix build failures with sparse check

commit bb3f38c3c5b759163e09b9152629cc789731de47 upstream.

We should avoid using the space character when passing arguments to
clang, because static code analysis check tool such as sparse may
misinterpret the arguments followed by spaces as build targets hence
cause the build to fail.

Signed-off-by: David Lin <dtwlin@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
[nc: Backport to 4.9; adjust context]
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>