soc/tegra: Implement runtime check for Tegra SoCs

Subsequent patches will move some of the initialization code from SoC
setup code to regular initcalls. To prevent breakage on other SoCs in
multi-platform builds, these initcalls need to check that they indeed
run on Tegra.

Signed-off-by: Thierry Reding <treding@nvidia.com>

include/soc/tegra/common.h

@@ -0,0 +1,14 @@
+/*
+ * Copyright (C) 2014 NVIDIA Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __SOC_TEGRA_COMMON_H__
+#define __SOC_TEGRA_COMMON_H__
+
+bool soc_is_tegra(void);
+
+#endif /* __SOC_TEGRA_COMMON_H__ */