Tegra30: Add AVP (arm720t) files

This provides SPL support for T30 boards - AVP early init, plus
CPU (A9) init/jump to main U-Boot.

Some changes were made to Tegra20 cpu.c to move common routines
into tegra-common/cpu.c and reduce code duplication.

Signed-off-by: Tom Warren <twarren@nvidia.com>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/cpu/arm720t/tegra-common/Makefile b/arch/arm/cpu/arm720t/tegra-common/Makefile
index febd2e3..6cbc6ad 100644
--- a/arch/arm/cpu/arm720t/tegra-common/Makefile
+++ b/arch/arm/cpu/arm720t/tegra-common/Makefile
@@ -28,6 +28,7 @@
 LIB	= $(obj)libtegra-common.o
 
 COBJS-$(CONFIG_SPL_BUILD) += spl.o
+COBJS-y	+= cpu.o
 
 SRCS	:= $(COBJS-y:.o=.c)
 OBJS	:= $(addprefix $(obj),$(COBJS-y))