ARM: zynq: add separate configuration for ZC702 and ZC706

Prior to this commit, ZC702 and ZC706 shared the same configuration
and were built as follows:

ZC702: make zynq_zc70x_defconfig && make
ZC706: make zynq_zc70x_defconfig && make DEVICE_TREE=zynq-zc706

This commit introduces separate configuration for them, which makes
the next commit much easier.

Going forward, the recommended build commands are:

ZC702: make zynq_zc702_defconfig && make
ZC706: make zynq_zc706_defconfig && make

Although the old work flow is still supported, CONFIG_TARGET_ZC70X
has been marked as deprecated.  If used, the warning message is
shown to prompt users to switch to the new scheme.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/board/xilinx/zynq/Makefile b/board/xilinx/zynq/Makefile
index 054c3d8..3979347 100644
--- a/board/xilinx/zynq/Makefile
+++ b/board/xilinx/zynq/Makefile
@@ -13,3 +13,13 @@
 
 # Suppress "warning: function declaration isn't a prototype"
 CFLAGS_REMOVE_ps7_init_gpl.o := -Wstrict-prototypes
+
+# Warn if CONFIG_TARGET_ZYNQ_ZC70X is enabled
+ifeq ($(CONFIG_TARGET_ZYNQ_ZC70X),y)
+ifeq ($(CONFIG_SPL_BUILD),y)
+$(warning CONFIG_TARGET_ZYNQ_ZC70X is deprecated.)
+$(warning Enable CONFIG_TARGET_ZYNQ_ZC702 or CONFIG_TARGET_ZYNQ_706 instead.)
+$(warning "make zynq_zc70x_defconfig" is also deprecated.)
+$(warning Use "make zynq_zc702_defconfig" or "make zynq_zc706_defconfig".)
+endif
+endif