kexec-tools: update to 2.0.26

kexec-tools: update to 2.0.26

Release Notes:
- 2.0.22: https://www.spinics.net/lists/kexec/msg26864.html
- 2.0.23: https://www.spinics.net/lists/kexec/msg27693.html
- 2.0.24: https://www.spinics.net/lists/kexec/msg28922.html
- 2.0.25: https://lore.kernel.org/all/YuYl22cyGldQQc5m@vergenet.net/
- 2.0.26: https://www.spinics.net/lists/kexec/msg30743.html

Remove upstreamed patch:
- 001-arm-do-not-copy-magic-4-bytes-of-appended-DTB-in-zIm.patch

Tested-by: Linhui Liu <liulinhui36@gmail.com> # x86_64
Signed-off-by: Nick Hainke <vincent@systemli.org>