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.py

@@ -297,5 +297,6 @@ class SysA(SysGeneral):
         self.get_file("http://ftp.gnu.org/gnu/make/make-3.82.tar.gz")
 
         # linux kernel 2.6.16.62
-        # for some reason this is no longer on kernel.org
-        self.get_file("https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/snapshot/linux-2.6.16.62.tar.gz")
+        self.get_file(["https://cdn.kernel.org/pub/linux/kernel/v4.x/linux-4.9.10.tar.gz",
+            "http://linux-libre.fsfla.org/pub/linux-libre/releases/4.9.10-gnu/deblob-4.9",
+            "http://linux-libre.fsfla.org/pub/linux-libre/releases/4.9.10-gnu/deblob-check"])