SystemServer: Boot into graphical mode even if there's no video hardware

SystemServer had safety fallbacks to boot into text mode if the user
errorneously specified graphical mode but no video hardware was present.
As it's now possible to do exactly this intentionally, we should allow
it. This would of course make WindowServer fall over and die if
configured improperly, but if you're messing with the kernel command
line in strange ways, you should be able to fix that.

Userland/Services/SystemServer/main.cpp

@@ -76,9 +76,7 @@ static ErrorOr<void> determine_system_mode()
     // FIXME: Support more than one framebuffer detection
     struct stat file_state;
     int rc = lstat("/dev/fb0", &file_state);
-    if (rc < 0 && g_system_mode == "graphical") {
-        g_system_mode = "text";
-    } else if (rc == 0 && g_system_mode == "text") {
+    if (rc == 0 && g_system_mode == "text") {
         dbgln("WARNING: Text mode with framebuffers won't work as expected! Consider using 'fbdev=off'.");
     }
     dbgln("System in {} mode", g_system_mode);