Tegra30: Add/enable Cardhu build (T30 reference board)

This build is stripped down. It boots to the command prompt.
GPIO is the only peripheral supported. Others TBD.

include/configs/tegra-common.h now holds common config options
for Tegra SoCs.

Signed-off-by: Tom Warren <twarren@nvidia.com>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
diff --git a/board/nvidia/cardhu/Makefile b/board/nvidia/cardhu/Makefile
new file mode 100644
index 0000000..913f1ce
--- /dev/null
+++ b/board/nvidia/cardhu/Makefile
@@ -0,0 +1,44 @@
+#
+#  (C) Copyright 2010-2012
+#  NVIDIA Corporation <www.nvidia.com>
+#
+#
+#  See file CREDITS for list of people who contributed to this
+#  project.
+#
+#  This program is free software; you can redistribute it and/or
+#  modify it under the terms of the GNU General Public License as
+#  published by the Free Software Foundation; either version 2 of
+#  the License, or (at your option) any later version.
+#
+#  This program is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#  GNU General Public License for more details.
+#
+#  You should have received a copy of the GNU General Public License
+#  along with this program; if not, write to the Free Software
+#  Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+#  MA 02111-1307 USA
+#
+
+include $(TOPDIR)/config.mk
+
+LIB	= $(obj)lib$(BOARD).o
+
+COBJS	:= $(BOARD).o
+
+SRCS	:= $(COBJS:.o=.c)
+OBJS	:= $(addprefix $(obj),$(COBJS))
+
+$(LIB):	$(obj).depend $(OBJS)
+	$(call cmd_link_o_target, $(OBJS))
+
+#########################################################################
+
+# defines $(obj).depend target
+include $(SRCTREE)/rules.mk
+
+sinclude $(obj).depend
+
+#########################################################################