kbuild: remove redundant 'set -e' from filechk_offsets

The filechk macro in scripts/Kbuild.include already sets 'set -e'.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

scripts/Makefile.lib

@@ -406,7 +406,7 @@ endef
 # Use filechk to avoid rebuilds when a header changes, but the resulting file
 # does not
 define filechk_offsets
-	(set -e; \
+	( \
 	 echo "#ifndef $2"; \
 	 echo "#define $2"; \
 	 echo "/*"; \