scripts/config: fix variable substitution command
scripts/config: fix variable substitution command

Commit 229455bc02b87f7128f190c4491b4ceffff38648 accidentally changed the
separator between sed `s' command and its parameters from ':' to '/'.

Revert this change.

Reported-and-tested-by: Linus Walleij <9cd9d802d23c0ed5e224beabf4ae4a5c478746ef@linaro.org>
Signed-off-by: Clement Chauplannaz <6eba3fbd1488dbe88116f55e129ca9b60964190a@gmail.com>
Signed-off-by: Michal Marek <0c835876a532a476f30fdb1f6e963bae6c5a1a04@suse.cz>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs