Add modification date to manpage header instead of the section

"System Manager's Manual" or similar is way less interesting.

Change-Id: I45c5d6a2316c51a57a49fd010682dc3f0f915382
Signed-off-by: Stefan Tauner <stefan.tauner@gmx.at>
Reviewed-on: https://review.coreboot.org/21822
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/Makefile b/Makefile
index 6806e14..68b9e9c 100644
--- a/Makefile
+++ b/Makefile
@@ -1384,7 +1384,7 @@
 
 $(PROGRAM).8: $(PROGRAM).8.tmpl
 	@# Add the man page change date and version to the man page
-	@sed -e 's#.TH FLASHROM 8 ".*".*#.TH FLASHROM 8 "$(MAN_DATE)" "$(VERSION)"#' <$< >$@
+	@sed -e 's#.TH FLASHROM 8 .*#.TH FLASHROM 8 "$(MAN_DATE)" "$(VERSION)" "$(MAN_DATE)"#' <$< >$@
 
 install: $(PROGRAM)$(EXEC_SUFFIX) $(PROGRAM).8
 	mkdir -p $(DESTDIR)$(PREFIX)/sbin