tegra: move common features to a common makefile

For Non-Nvidia boards to include newly added features (like emc clock
scaling) it would be necessary to add each feature to their own board
Makefile. This is because currently the top Makefile automaticly includes
these features only for Nvidia boards.

This patch adds a simple Makefile include so all new features become
available for non-Nvidia board vendors.

Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Tom Warren <twarren@nvidia.com>
Cc: Thierry Reding <thierry.reding@avionic-design.de>
Cc: Lucas Stach <dev@lynxeye.de>
Signed-off-by: Marc Dietrich <marvin24@gmx.de>
Acked-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Tom Warren <twarren@nvidia.com>
diff --git a/board/nvidia/common/Makefile b/board/nvidia/common/Makefile
index a93d458..f6f419e 100644
--- a/board/nvidia/common/Makefile
+++ b/board/nvidia/common/Makefile
@@ -25,9 +25,7 @@
 
 LIB	= $(obj)lib$(VENDOR).o
 
-COBJS-y += board.o
-COBJS-$(CONFIG_SPI_UART_SWITCH) += uart-spi-switch.o
-COBJS-$(CONFIG_TEGRA_CLOCK_SCALING) += emc.o
+include common.mk
 
 COBJS	:= $(COBJS-y)
 SRCS	:= $(SOBJS:.o=.S) $(COBJS:.o=.c)
diff --git a/board/nvidia/common/common.mk b/board/nvidia/common/common.mk
new file mode 100644
index 0000000..bd6202c
--- /dev/null
+++ b/board/nvidia/common/common.mk
@@ -0,0 +1,4 @@
+# common options for all tegra boards
+COBJS-y	+= ../../nvidia/common/board.o
+COBJS-$(CONFIG_SPI_UART_SWITCH) += ../../nvidia/common/uart-spi-switch.o
+COBJS-$(CONFIG_TEGRA_CLOCK_SCALING) += ../../nvidia/common/emc.o