drm/panfrost: Add an helper to check the GPU generation

All models with an ID >= 0x1000 are Bifrost GPUs for now (might change
with new gens).
Suggested-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190618081648.17297-4-boris.brezillon@collabora.com

drivers/gpu/drm/panfrost/panfrost_device.h

@@ -110,6 +110,11 @@ static inline int panfrost_model_cmp(struct panfrost_device *pfdev, s32 id)
 	return match_id - id;
 }
 
+static inline bool panfrost_model_is_bifrost(struct panfrost_device *pfdev)
+{
+	return panfrost_model_cmp(pfdev, 0x1000) >= 0;
+}
+
 static inline bool panfrost_model_eq(struct panfrost_device *pfdev, s32 id)
 {
 	return !panfrost_model_cmp(pfdev, id);