egl: refactor dri2_create_screen() into three separate functions

Split the create_screen into:
 - create screen
 - setup/bind extensions
 - setup screen

This will allow us to reuse the latter two on egl/drm. Said platform
does create its own screen and attempts to reinvent the later two
functions itself.

Since the GBM ones tend to get out of sync quite often, and there is no
distinct reason why it does so we'll drop them with latter commits.

v2: disp -> dpy for the Android platform.
v3: use correct goto label (Rob)

Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Tested-by: Rob Herring <robh@kernel.org>
diff --git a/src/egl/drivers/dri2/egl_dri2.c b/src/egl/drivers/dri2/egl_dri2.c
index 1c3d00c..787c377 100644
--- a/src/egl/drivers/dri2/egl_dri2.c
+++ b/src/egl/drivers/dri2/egl_dri2.c
@@ -694,14 +694,12 @@
    }
 }
 
-/* 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.
+/* All platforms but DRM call this function to create the screen and populate
+ * the driver_configs. DRM inherits that information from its display - GBM.
  */
 EGLBoolean
 dri2_create_screen(_EGLDisplay *disp)
 {
-   const __DRIextension **extensions;
    struct dri2_egl_display *dri2_dpy = dri2_egl_display(disp);
 
    if (dri2_dpy->image_driver) {
@@ -744,27 +742,28 @@
    }
 
    dri2_dpy->own_dri_screen = 1;
+   return EGL_TRUE;
+}
+
+EGLBoolean
+dri2_setup_extensions(_EGLDisplay *disp)
+{
+   struct dri2_egl_display *dri2_dpy = dri2_egl_display(disp);
+   const struct dri2_extension_match *mandatory_core_extensions;
+   const __DRIextension **extensions;
 
    extensions = dri2_dpy->core->getExtensions(dri2_dpy->dri_screen);
 
-   if (dri2_dpy->image_driver || dri2_dpy->dri2) {
-      if (!dri2_bind_extensions(dri2_dpy, dri2_core_extensions, extensions, false))
-         goto cleanup_dri_screen;
-   } else {
-      assert(dri2_dpy->swrast);
-      if (!dri2_bind_extensions(dri2_dpy, swrast_core_extensions, extensions, false))
-         goto cleanup_dri_screen;
-   }
+   if (dri2_dpy->image_driver || dri2_dpy->dri2)
+      mandatory_core_extensions = dri2_core_extensions;
+   else
+      mandatory_core_extensions = swrast_core_extensions;
+
+   if (!dri2_bind_extensions(dri2_dpy, mandatory_core_extensions, extensions, false))
+      return EGL_FALSE;
 
    dri2_bind_extensions(dri2_dpy, optional_core_extensions, extensions, true);
-   dri2_setup_screen(disp);
-
    return EGL_TRUE;
-
- cleanup_dri_screen:
-   dri2_dpy->core->destroyScreen(dri2_dpy->dri_screen);
-
-   return EGL_FALSE;
 }
 
 /**