hw/ppc/Kconfig: Add missing SERIAL_ISA dependency to POWERNV machine

The machine calls serial_hds_isa_init() which is provided by serial-isa.c,
guarded by SERIAL_ISA.

Signed-off-by: Bernhard Beschow <shentey@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20240814181534.218964-4-shentey@gmail.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
1 file changed