Tegra30: Add generic Tegra30 build support

This patch adds basic Tegra30 (T30) build support - no specific
board is targeted.

Signed-off-by: Tom Warren <twarren@nvidia.com>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
diff --git a/Makefile b/Makefile
index 3305e8c..ff72deb 100644
--- a/Makefile
+++ b/Makefile
@@ -348,7 +348,7 @@
 ifeq ($(SOC),exynos)
 LIBS-y += $(CPUDIR)/s5p-common/libs5p-common.o
 endif
-ifeq ($(SOC),tegra20)
+ifneq ($(CONFIG_TEGRA),)
 LIBS-y += arch/$(ARCH)/cpu/$(SOC)-common/lib$(SOC)-common.o
 LIBS-y += arch/$(ARCH)/cpu/tegra-common/libcputegra-common.o
 LIBS-y += $(CPUDIR)/tegra-common/libtegra-common.o
@@ -413,7 +413,7 @@
 ALL-$(CONFIG_OF_SEPARATE) += $(obj)u-boot.dtb $(obj)u-boot-dtb.bin
 
 # enable combined SPL/u-boot/dtb rules for tegra
-ifeq ($(SOC),tegra20)
+ifneq ($(CONFIG_TEGRA),)
 ifeq ($(CONFIG_OF_SEPARATE),y)
 ALL-y += $(obj)u-boot-dtb-tegra.bin
 else
@@ -530,7 +530,7 @@
 			conv=notrunc 2>/dev/null
 		cat $(obj)spl/u-boot-spl-pad.img $(obj)u-boot.img > $@
 
-ifeq ($(SOC),tegra20)
+ifneq ($(CONFIG_TEGRA),)
 ifeq ($(CONFIG_OF_SEPARATE),y)
 nodtb=dtb
 dtbfile=$(obj)u-boot.dtb