scripts: add nconf into gitignore file

scripts/kconfig/nconf is generated by 'make nconfig',
add it into .gitignore.

Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
diff --git a/scripts/kconfig/.gitignore b/scripts/kconfig/.gitignore
index 6a36a76..624f650 100644
--- a/scripts/kconfig/.gitignore
+++ b/scripts/kconfig/.gitignore
@@ -17,6 +17,7 @@
 #
 conf
 mconf
+nconf
 qconf
 gconf
 kxgettext