[U-Boot] [PATCH v2] README.kconfig: document backward compatibility "make *_config"

[Masahiro Yamada]

Commit 3ff291f371fa9858426774f3732924bacb61ed1c
(kconfig: convert Kconfig helper script into a shell script)
restored "<board>_config" target for backward compatibility.
It should be documented.

Signed-off-by: Masahiro Yamada <yamada.m at jp.panasonic.com>
---

Changes in v2:
  - Update the commit description

 doc/README.kconfig     | 7 +++++++
 scripts/multiconfig.sh | 1 +
 2 files changed, 8 insertions(+)

diff --git a/doc/README.kconfig b/doc/README.kconfig
index cd549a8..3aad5b4 100644
--- a/doc/README.kconfig
+++ b/doc/README.kconfig
@@ -114,6 +114,13 @@ See below for how each configuration target works in U-Boot:
   coalesced together with "<condition:>" prefix for each line as shown above.
   This file can be used as an input of "defconfig" target.
 
+- <board>_config
+
+  This does not exist in Linux's Kconfig.
+  Prior to Kconfig, in U-Boot, "make <board>_config" was used for the
+  configuration.  It is still supported for backward compatibility and
+  its behavior is the same as "make <board>_defconfig".
+
 
 Migration steps to Kconfig
 --------------------------
diff --git a/scripts/multiconfig.sh b/scripts/multiconfig.sh
index 56cf0c2..4190798 100644
--- a/scripts/multiconfig.sh
+++ b/scripts/multiconfig.sh
@@ -248,6 +248,7 @@ case $target in
 *_defconfig)
 	do_board_defconfig $target;;
 *_config)
+	# backward compatibility
 	do_board_defconfig ${target%_config}_defconfig;;
 silentoldconfig)
 	do_silentoldconfig;;
-- 
1.9.1