kunit: tool: update riscv QEMU config with new serial dependency

kunit: tool: update riscv QEMU config with new serial dependency

The config for the serial console for riscv,
CONFIG_SERIAL_EARLYCON_RISCV_SBI, added a dependency,
CONFIG_RISCV_SBI_V01, at some point, so add that in to the base arch
config.

Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>