qapi/ui: Drop temporary 'prefix'

Recent commit "qapi: Smarter camel_to_upper() to reduce need for
'prefix'" added a temporary 'prefix' to delay changing the generated
code.

Revert it.  This improves DisplayGLMode's generated enumeration
constant prefix from DISPLAYGL_MODE to DISPLAY_GL_MODE.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20240904111836.3273842-9-armbru@redhat.com>

ui/spice-core.c

@@ -840,7 +840,7 @@ static void qemu_spice_init(void)
                          "incompatible with -spice port/tls-port");
             exit(1);
         }
-        egl_init(qemu_opt_get(opts, "rendernode"), DISPLAYGL_MODE_ON, &error_fatal);
+        egl_init(qemu_opt_get(opts, "rendernode"), DISPLAY_GL_MODE_ON, &error_fatal);
         spice_opengl = 1;
     }
 #endif