Fix missing includes of qemu/log.h, which broke compilation with the
simple trace backend (the default backend pulls in log.h implicitly
via trace.h).

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Sergey Fedorov <sergey.fedorov@linaro.org>
Tested-by: Sergey Fedorov <sergey.fedorov@linaro.org>
Message-id: 1466416634-9798-1-git-send-email-peter.maydell@linaro.org