mmc: tegra: convert to device tree support only

When compiling a kernel that supports only Tegra30 and not Tegra20,
the SDHCI driver will fail to compile since the of_match_device() failure
fallback code unconditinally references soc_data_tegra20, which is only
compiled in when Tegra20 support is enabled.

In Kernel 3.7, both Tegra20 and Tegra30 will only support booting using
device tree, Hence, there is never a need to fall back to using
soc_data_tegra20 if of_mach_device() fails. Instead, make this case an
error. This removes the reference to soc_data_tegra20, and hence solves
the compile failure.
Signed-off-by: Joseph Lo <josephl@nvidia.com>
Tested-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Chris Ball <cjb@laptop.org>

drivers/mmc/host/sdhci-tegra.c

@@ -257,10 +257,9 @@ static int __devinit sdhci_tegra_probe(struct platform_device *pdev)
 	int rc;
 
 	match = of_match_device(sdhci_tegra_dt_match, &pdev->dev);
-	if (match)
-		soc_data = match->data;
-	else
-		soc_data = &soc_data_tegra20;
+	if (!match)
+		return -EINVAL;
+	soc_data = match->data;
 
 	host = sdhci_pltfm_init(pdev, soc_data->pdata);
 	if (IS_ERR(host))