package/libopenssl: remove patch numbering within patch

Fixes:

  package/libopenssl/0006-Add-linux-x86-latomic-target.patch:4: generate your patches with 'git format-patch -N'

In:

  https://gitlab.com/buildroot.org/buildroot/-/jobs/4763324039

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/libopenssl/0006-Add-linux-x86-latomic-target.patch

@@ -1,7 +1,7 @@
 From c80a60dca209813c33ab3d2794bc32d84c12d033 Mon Sep 17 00:00:00 2001
 From: Bernd Kuhls <bernd@kuhls.net>
 Date: Fri, 28 Jul 2023 17:11:25 +0200
-Subject: [PATCH 1/1] Add linux-x86-latomic target
+Subject: [PATCH] Add linux-x86-latomic target
 
 Upstream: https://github.com/openssl/openssl/pull/21590