cocoa: Suppress Cocoa window with -display

Do not open a Cocoa window when another display is selected that will be
initialized later. The Cocoa display cannot be selected with -display,
so there is no need to check its argument.
Signed-off-by: NRainer Müller <raimue@codingfarm.de>
Reviewed-by: NAndreas Färber <andreas.faerber@web.de>
Message-id: 1441807710-25431-1-git-send-email-raimue@codingfarm.de
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

ui/cocoa.m

@@ -1148,6 +1148,7 @@ int main (int argc, const char * argv[]) {
                 !strcmp(opt, "-nographic") ||
                 !strcmp(opt, "-version") ||
                 !strcmp(opt, "-curses") ||
+                !strcmp(opt, "-display") ||
                 !strcmp(opt, "-qtest")) {
                 return qemu_main(gArgc, gArgv, *_NSGetEnviron());
             }