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/usb/host/Kconfig b/drivers/usb/host/Kconfig
index cbfb54c..f0a9ed2 100644
--- a/drivers/usb/host/Kconfig
+++ b/drivers/usb/host/Kconfig
@@ -203,7 +203,7 @@
 
 config USB_EHCI_TEGRA
 	bool "Support for NVIDIA Tegra on-chip EHCI USB controller"
-	depends on TEGRA
+	depends on ARCH_TEGRA
 	---help---
 	  Enable support for Tegra on-chip EHCI USB controller