rename symbol: CONFIG_TEGRA -> CONFIG_ARCH_TEGRA

Have this symbol follow the pattern of all other such symbols.

Signed-off-by: Trevor Woerner <twoerner@gmail.com>
diff --git a/drivers/mmc/Kconfig b/drivers/mmc/Kconfig
index 8f0df56..3c4f057 100644
--- a/drivers/mmc/Kconfig
+++ b/drivers/mmc/Kconfig
@@ -616,7 +616,7 @@
 
 config MMC_SDHCI_TEGRA
 	bool "SDHCI platform support for the Tegra SD/MMC Controller"
-	depends on TEGRA
+	depends on ARCH_TEGRA
 	select BOUNCE_BUFFER
 	default y
 	help