Dist: Fix Linux desktop file launch argument

misc/dist/linux/godot.desktop

@@ -2,7 +2,7 @@
 Name=Godot Engine
 GenericName=Libre game engine
 Comment=Multi-platform 2D and 3D game engine with a feature rich editor
-Exec=godot -pm
+Exec=godot -p
 Icon=godot
 Terminal=false
 Type=Application