egl_dri2: add a note about dri2_create_screen

The function is not called by platform_drm. As such one needs to
pay special attention at teardown.

v2: Fix the comment block. Spotted by Ken.

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
Reviewed-and-tested-by: Kenneth Graunke <kenneth@whitecape.org> (v1)

src/egl/drivers/dri2/egl_dri2.c

@@ -543,6 +543,10 @@ dri2_setup_screen(_EGLDisplay *disp)
    }
 }
 
+/* All platforms but DRM call this function to create the screen, query the
+ * dri extensions, setup the vtables and populate the driver_configs.
+ * DRM inherits all that information from its display - GBM.
+ */
 EGLBoolean
 dri2_create_screen(_EGLDisplay *disp)
 {