artecgroup/Kconfig, linutop/Kconfig: Add comment to endif

All other Kconfig files at the mainboard vendor level have a comment
on "endif" matching the corresponding "if", except these two.

Change-Id: Ib03c4552c670178d6b09a2ca3037ee29e3524a2f
Signed-off-by: Daniele Forsi <dforsi@gmail.com>
Reviewed-on: http://review.coreboot.org/6396
Tested-by: build bot (Jenkins)
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
diff --git a/src/mainboard/linutop/Kconfig b/src/mainboard/linutop/Kconfig
index 7209916..75b657a 100644
--- a/src/mainboard/linutop/Kconfig
+++ b/src/mainboard/linutop/Kconfig
@@ -14,4 +14,4 @@
 
 source "src/mainboard/linutop/linutop1/Kconfig"
 
-endif
+endif # VENDOR_LINUTOP