gcc-runtime: remove bashism

gcc-runtime: remove bashism

Debian 12 no longer supports replacing dash with bash as default shell.
Therefore to achieve compatibility with Debian 12, all bashisms need
to be removed.

Shell comparison via == gives an error with dash and thus the condition
is always false.

Signed-off-by: Peter Marko <peter.marko@siemens.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 3723b26f82219ff71823335d550dbf29086d63d4)
Signed-off-by: Steve Sakoman <steve@sakoman.com>