kconfig: split images.c out of qconf.cc/gconf.c to fix gconf warnings

Currently, images.c is included by qconf.cc and gconf.c.
qconf.cc uses all of xpm_* arrays, but gconf.c only some of them.
Hence, lots of "... defined but not used" warnings are displayed
while compiling gconf.c

Splitting out images.c fixes the warnings.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/scripts/kconfig/gconf.c b/scripts/kconfig/gconf.c
index 2d4e5a1..b3d438c 100644
--- a/scripts/kconfig/gconf.c
+++ b/scripts/kconfig/gconf.c
@@ -9,7 +9,7 @@
 
 #include <stdlib.h>
 #include "lkc.h"
-#include "images.c"
+#include "images.h"
 
 #include <glade/glade.h>
 #include <gtk/gtk.h>