[media] st-hva: hva_dbg_summary() should be static

As reported by gcc:

drivers/media/platform/sti/hva/hva-v4l2.c:227:6: warning: no previous prototype for 'hva_dbg_summary' [-Wmissing-prototypes]
 void hva_dbg_summary(struct hva_ctx *ctx)
      ^~~~~~~~~~~~~~~

This function is used only internally, so make it static.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/platform/sti/hva/hva-v4l2.c

@@ -224,7 +224,7 @@ static int hva_open_encoder(struct hva_ctx *ctx, u32 streamformat,
 	return ret;
 }
 
-void hva_dbg_summary(struct hva_ctx *ctx)
+static void hva_dbg_summary(struct hva_ctx *ctx)
 {
 	struct device *dev = ctx_to_dev(ctx);
 	struct hva_streaminfo *stream = &ctx->streaminfo;