Update the linux kernel for sysb/c to 4.9.10.

- We do not use latest 4.9.x because it relies on a new version of
  binutils, while older versions do not. (Note: we should be able to go
  a bit newer but I didn't bother testing >50 versions to figure this
  out).
- We do not use newer kernel versions because they require one or more
  of (new perl, new binutils, new make, new gcc, new bison, new tar).
- sysb and sysc are updated to use the SATA (libata) subsystem (aka sda)
  instead of IDE-emulating SATA subsystem (aka hda) which is now
  available to us.
- While theoretically according to docs 4.9 should work OOTB with our
  version of binutils this is not the case, so we have to do a bit of
  (interesting) patching. But this does not break anything.
- Thankfully serial support in 4.9 is not screwed over like it is in 2.6
  so we can revert to that.
- 4.9 has the linux-libre project at our disposal, instead of gNewSense.
  So we use this. Unfortunatley that takes forever because we have to
  use sed because our version of gawk is too old/buggy. :( I plan to
  introduce very shortly 1. parallelism 2. 'sysc snapshot' which will
  start from sysc to avoid this. I do not want to use linux-libre
  tarballs because they make modificiations directly from this script
  (aka not easily verifiable, use the source!) and this script allows
  for much greater flexibility.
- We compile the initramfs ahead-of-build using the in-tree cpio
  generator instead of also building cpio to use less packages. We do
  NOT build the initramfs into the kernel like 2.6 (unsupported).
- Oh and fix a kexec-tools checksum.

sysa/linux-4.9.10/patches/remove-kconfig.patch

@@ -0,0 +1,23 @@
+SPDX-FileCopyrightText: 2021 fosslinux <fosslinux@aussies.space>
+
+SPDX-License-Identifier: GPL-2.0-only
+
+kconfig uses gperf, which we don't have at this stage. We manually generate
+everything (in the actual script) that is actually required within kconfig,
+and forgo everything that is not really required for the build.
+
+--- Makefile	2021-07-30 21:25:43.577592065 +1000
++++ Makefile	2021-07-30 21:26:40.349015612 +1000
+@@ -547,10 +547,10 @@
+ export KBUILD_DEFCONFIG KBUILD_KCONFIG
+ 
+ config: scripts_basic outputmakefile FORCE
+-	$(Q)$(MAKE) $(build)=scripts/kconfig $@
++	$(Q)true
+
+ %config: scripts_basic outputmakefile FORCE
+-	$(Q)$(MAKE) $(build)=scripts/kconfig $@
++	true
+
+ else
+ # ===========================================================================