Merge tag 'doc-2023-10-rc4' of https://source.denx.de/u-boot/custodians/u-boot-efi

Pull request for doc-2023-10-rc4

Documentation:

* Fix documentation for TI boards
* Describe running on VirtualBox
* List build dependencies for building documenation
* Add references to U-Boot talks

Other:

* Fix error handling in the setexpr command (printf_str)