arm: Tegra2: add support for A9 CPU init

Signed-off-by: Tom Warren <twarren@nvidia.com>
diff --git a/arch/arm/cpu/armv7/start.S b/arch/arm/cpu/armv7/start.S
index 6387b8b..2929fc7 100644
--- a/arch/arm/cpu/armv7/start.S
+++ b/arch/arm/cpu/armv7/start.S
@@ -70,6 +70,18 @@
 _TEXT_BASE:
 	.word	CONFIG_SYS_TEXT_BASE
 
+#ifdef CONFIG_TEGRA2
+/*
+ * Tegra2 uses 2 separate CPUs - the AVP (ARM7TDMI) and the CPU (dual A9s).
+ * U-Boot runs on the AVP first, setting things up for the CPU (PLLs,
+ * muxes, clocks, clamps, etc.). Then the AVP halts, and expects the CPU
+ * to pick up its reset vector, which points here.
+ */
+.globl _armboot_start
+_armboot_start:
+        .word _start
+#endif
+
 /*
  * These are defined in the board-specific linker script.
  */