kconfig: add board Kconfig and defconfig files

This commit adds:
 - arch/${ARCH}/Kconfig
    provide a menu to select target boards
 - board/${VENDOR}/${BOARD}/Kconfig or board/${BOARD}/Kconfig
    set CONFIG macros to the appropriate values for each board
 - configs/${TARGET_BOARD}_defconfig
    default setting of each board

(This commit was automatically generated by a conversion script
based on boards.cfg)

In Linux Kernel, defconfig files are located under
arch/${ARCH}/configs/ directory.
It works in Linux Kernel since ARCH is always given from the
command line for cross compile.

But in U-Boot, ARCH is not given from the command line.
Which means we cannot know ARCH until the board configuration is done.
That is why all the "*_defconfig" files should be gathered into a
single directory ./configs/.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/powerpc/cpu/mpc86xx/Kconfig b/arch/powerpc/cpu/mpc86xx/Kconfig
new file mode 100644
index 0000000..f0ff441
--- /dev/null
+++ b/arch/powerpc/cpu/mpc86xx/Kconfig
@@ -0,0 +1,30 @@
+menu "mpc86xx CPU"
+	depends on MPC86xx
+
+config SYS_CPU
+	string
+	default "mpc86xx"
+
+choice
+	prompt "Target select"
+
+config TARGET_SBC8641D
+	bool "Support sbc8641d"
+
+config TARGET_MPC8610HPCD
+	bool "Support MPC8610HPCD"
+
+config TARGET_MPC8641HPCN
+	bool "Support MPC8641HPCN"
+
+config TARGET_XPEDITE517X
+	bool "Support xpedite517x"
+
+endchoice
+
+source "board/freescale/mpc8610hpcd/Kconfig"
+source "board/freescale/mpc8641hpcn/Kconfig"
+source "board/sbc8641d/Kconfig"
+source "board/xes/xpedite517x/Kconfig"
+
+endmenu