linux/generic/hack-5.15: add missing patch headers

This patches does not have a valid patch headers and does not apply on
an external git tree with 'git am'. To fix this add the missing headers.

Signed-off-by: Florian Eckert <fe@dev.tdt.de>

target/linux/generic/hack-5.15/205-kconfig-exit.patch

@@ -1,3 +1,14 @@
+From 300d26562ce4dc427154cb247beb75db4b1f0774 Mon Sep 17 00:00:00 2001
+From: OpenWrt community <openwrt-devel@lists.openwrt.org>
+Date: Wed, 13 Jul 2022 13:29:57 +0200
+Subject: [PATCH] scripts/Kconfig: Kconfig exit
+
+---
+ scripts/kconfig/conf.c | 2 ++
+ 1 file changed, 2 insertions(+)
+
+diff --git a/scripts/kconfig/conf.c b/scripts/kconfig/conf.c
+index 5d84b44a2a2a..d279d95aac92 100644
 --- a/scripts/kconfig/conf.c
 +++ b/scripts/kconfig/conf.c
 @@ -435,6 +435,8 @@ static int conf_sym(struct menu *menu)
@@ -9,3 +20,5 @@
  			newval = oldval;
  			break;
  		case '?':
+-- 
+