Add linux headers 5.10.41.

Needed for kexec-tools.

Not equivalent to kernel version; kernel API is stable and does not
change. Therefore we can use any (latest) version.

sysa/linux-headers-5.10.41/patches/winsize.patch

@@ -0,0 +1,20 @@
+SPDX-FileCopyrightText: 2021 fosslinux <fosslinux@aussies.space>
+
+SPDX-License-Identifier: GPL-2.0-only
+
+--- include/uapi/asm-generic/termios.h.bak	2021-07-23 14:23:51.330460544 +1000
++++ include/uapi/asm-generic/termios.h	2021-07-23 19:08:27.112810109 +1000
+@@ -12,13 +12,6 @@
+ #include <asm/termbits.h>
+ #include <asm/ioctls.h>
+ 
+-struct winsize {
+-	unsigned short ws_row;
+-	unsigned short ws_col;
+-	unsigned short ws_xpixel;
+-	unsigned short ws_ypixel;
+-};
+-
+ #define NCC 8
+ struct termio {
+ 	unsigned short c_iflag;		/* input mode flags */