tegra2: Add arch_cpu_init() to fire up Cortex-A9

We want to move away from a special Tegra2 start-up, and just use
arch_cpu_init() instead. However, if we run board_init_f() from boot
we need to build it for ARMv4T, since the Tegra's AVP start-up CPU
does not support ARMv7.

The effect of this is to do the AVP init earlier, and in
arch_cpu_init(), rather that board_early_init_f().

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>
diff --git a/arch/arm/cpu/armv7/tegra2/config.mk b/arch/arm/cpu/armv7/tegra2/config.mk
index 96c0795..f84fdc8 100644
--- a/arch/arm/cpu/armv7/tegra2/config.mk
+++ b/arch/arm/cpu/armv7/tegra2/config.mk
@@ -26,3 +26,9 @@
 
 # Use ARMv4 for Tegra2 - initial code runs on the AVP, which is an ARM7TDI.
 PLATFORM_CPPFLAGS += -march=armv4
+
+# Tegra has an ARMv4T CPU which runs board_init_f(), so we must build this
+# file with compatible flags
+ifdef CONFIG_TEGRA2
+CFLAGS_arch/arm/lib/board.o += -march=armv4t
+endif