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/configs/apalis-tk1_defconfig b/configs/apalis-tk1_defconfig
index 150941f..604a473 100644
--- a/configs/apalis-tk1_defconfig
+++ b/configs/apalis-tk1_defconfig
@@ -1,5 +1,5 @@
 CONFIG_ARM=y
-CONFIG_TEGRA=y
+CONFIG_ARCH_TEGRA=y
 CONFIG_SYS_TEXT_BASE=0x80110000
 CONFIG_SYS_MALLOC_F_LEN=0x2000
 CONFIG_ENV_SIZE=0x2000