hw/display/cirrus_vga: Fix code mis-indentation

While replacing fprintf() by qemu_log_mask() in commit
2b55f4d3, we incorrectly used a 'tab = 4 spaces'
alignment, leading to misindented new code. Fix now.

Reported-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20200529165436.23573-1-f4bug@amsat.org
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>