kunit: qemu_configs: sparc: use Zilog console

kunit: qemu_configs: sparc: use Zilog console

The driver for the 8250 console is not used, as no port is found.
Instead the prom0 bootconsole is used the whole time.
The prom driver translates '\n' to '\r\n' before handing of the message
off to the firmware. The firmware performs the same translation again.
In the final output produced by QEMU each line ends with '\r\r\n'.
This breaks the kunit parser, which can only handle '\r\n' and '\n'.

Use the Zilog console instead. It works correctly, is the one documented
by the QEMU manual and also saves a bit of codesize:
Before=4051011, After=4023326, chg -0.68%

Observed on QEMU 9.2.0.

Link: https://lore.kernel.org/r/20250214-kunit-qemu-sparc-console-v1-1-ba1dfdf8f0b1@linutronix.de
Fixes: 87c9c1631788 ("kunit: tool: add support for QEMU")
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>