Slightly improve readability of creating the south btidge by cnamging
type of a local variable to avoid some casts within function arguments
which makes some lines shorter and easier to read.
Also remove an unneded line break.

Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230117214545.5E191746369@zero.eik.bme.hu>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>