kbuild: remove trailing slash from devicetree/binding/ for descending

obj-* needs a trailing slash for a directory, but subdir-* does not
because it already implies a directory.

Also, change subdir-y to subdir- to ensure this is effective only
for cleaning targets.

This makes the cleaning log consistent. (no trailing slash)

Before:

  $ make clean
  CLEAN   Documentation/devicetree/bindings/

After:

  $ make clean
  CLEAN   Documentation/devicetree/bindings

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/Documentation/Makefile b/Documentation/Makefile
index d77bb607aea4..39569a2e1953 100644
--- a/Documentation/Makefile
+++ b/Documentation/Makefile
@@ -2,7 +2,8 @@
 # Makefile for Sphinx documentation
 #
 
-subdir-y := devicetree/bindings/
+# for cleaning
+subdir- := devicetree/bindings
 
 # Check for broken documentation file references
 ifeq ($(CONFIG_WARN_MISSING_DOCUMENTS),y)