kbuild: change filechk to surround the given command with { }

filechk_* rules often consist of multiple 'echo' lines. They must be
surrounded with { } or ( ) to work correctly. Otherwise, only the
string from the last 'echo' would be written into the target.

Let's take care of that in the 'filechk' in scripts/Kbuild.include
to clean up filechk_* rules.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

scripts/Kbuild.include

@@ -56,7 +56,7 @@ kecho := $($(quiet)kecho)
 define filechk
 	$(Q)set -e;				\
 	mkdir -p $(dir $@);			\
-	$(filechk_$(1)) > $@.tmp;		\
+	{ $(filechk_$(1)); } > $@.tmp;		\
 	if [ -r $@ ] && cmp -s $@ $@.tmp; then	\
 		rm -f $@.tmp;			\
 	else					\