OpenSystemsDevelopment / usbboot

* Remove the reference to LEDs flashing with mass-storage-gadget
  because this code was removed.
* Mention LUKS / rpi-otp-private-key in the secure-boot section.
* Add a link to the PIP
* Drop reference to make-boot-image - just use buildroot.

Update pieeprom to 2022-11-04

Fix a secure boot failure when booting from MMC (but not RPIBOOT)

Reduce the size of the windows installer by removing the
optional components. It will now just contain the MSD
firmware drive, the new mass-storage gadget (for writing
NVMe) and the recovery.

The optional components including secure-boot-example and
the Raspberry Pi Image can be downloaded from Github
without rebuilding this installer.

Add a helper batch file and shortcut for launching
the mass-storage-gadget.

tools: vcmailbox wrappers for managing 256 bit OTP private key

Update EEPROM to 2022-10-18

Also make the secure-boot-recovery pieeprom.original.bin a symlink
to ../pieeprom.original.bin. There's no need to have different
binaries so remove duplication.

Add a Python utility script to converts RSA public keys
from PEM format to the binary format required by the bootloader
and vice-versa.

Check for a directory instead of a file.

rpi-eeprom-digest: Add an option to verify RSA signed files.

Wrap the OpenSSL commands to verify the RSA signature in a .sig
file for a given image. This could be used to verify a signed
boot image or EEPROM image before attempting to install it.

Merge https://github.com/timg236/cm4-scripts/pull/1 to remove the
LED activity flashing because this conflicts with EMMC_EN_N_1V8
on CM3.

I've reverted the change that removed the explict modprobe of
libcomposite becuase that broke the gadgetfs support for me on CM4.

Add option to look for CM with specific USB path.

Force device/peripheral mode instead of relying on the OTG pin
because this might not work on CM4S.

Replace duplicated bootcode4.bin with links to bootcode4.bin / recovery.bin

This also resolve a startup issue CM4-S

Sync this with the version in tools. TODO - change the scripts
to use the version in tools instead.

bootcode4: Improved DDR setup for old (or missing) EEPROM images