memory: tegra: Don't invoke Tegra30+ specific memory timing setup on Tegra20

This fixes irrelevant "tegra-mc 7000f000.memory-controller: no memory
timings for RAM code 0 registered" warning message during of kernels
boot-up on Tegra20.

Fixes: a8d502fd ("memory: tegra: Squash tegra20-mc into common tegra-mc driver")
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Acked-by: Jon Hunter <jonathanh@nvidia.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/memory/tegra/mc.c

@@ -664,12 +664,13 @@ static int tegra_mc_probe(struct platform_device *pdev)
 		}
 
 		isr = tegra_mc_irq;
-	}
 
-	err = tegra_mc_setup_timings(mc);
-	if (err < 0) {
-		dev_err(&pdev->dev, "failed to setup timings: %d\n", err);
-		return err;
+		err = tegra_mc_setup_timings(mc);
+		if (err < 0) {
+			dev_err(&pdev->dev, "failed to setup timings: %d\n",
+				err);
+			return err;
+		}
 	}
 
 	mc->irq = platform_get_irq(pdev, 0);