kunit: tool: Use qboot on QEMU x86_64

As noted in [0], SeaBIOS (QEMU default) makes a mess of the terminal,
qboot does not.

It turns out this is actually useful with kunit.py, since the user is
exposed to this issue if they set --raw_output=all.

qboot is also faster than SeaBIOS, but it's is marginal for this
usecase.

[0] https://lore.kernel.org/all/CA+i-1C0wYb-gZ8Mwh3WSVpbk-LF-Uo+njVbASJPe1WXDURoV7A@mail.gmail.com/

Both SeaBIOS and qboot are x86-specific.

Link: https://lore.kernel.org/r/20250124-kunit-qboot-v1-1-815e4d4c6f7c@google.com
Signed-off-by: Brendan Jackman <jackmanb@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

tools/testing/kunit/qemu_configs/x86_64.py

@@ -7,4 +7,6 @@
 			   qemu_arch='x86_64',
 			   kernel_path='arch/x86/boot/bzImage',
 			   kernel_command_line='console=ttyS0',
-			   extra_qemu_params=[])
+			   # qboot is faster than SeaBIOS and doesn't mess up
+			   # the terminal.
+			   extra_qemu_params=['-bios', 'qboot.rom'])