[PATCH 1/7] doc: make pdfdocs: Specify texlive-xetex as a prerequisite

[Adriano Carvalho]

If I don't apt install texlive-xetex, this is what I get with docker.io/trini/u-boot-gitlab-ci-runner:jammy-20250714-25Jul2025:

uboot at 35c89b9ab70e:~/u-boot$ make pdfdocs
  HOSTCC  scripts/basic/fixdep
doc/Makefile:89: The 'xelatex' command was not found. Make sure you have it installed and in PATH to produce PDF output.
  SKIP    Sphinx pdfdocs target.

NOTE: This won't completely fix the pdfdocs target. See next commit(s).

Signed-off-by: Adriano Carvalho <adrianocarvalho.pt at gmail.com>
---
 doc/build/documentation.rst | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/doc/build/documentation.rst b/doc/build/documentation.rst
index 098c96a4c4f..68d7e11c572 100644
--- a/doc/build/documentation.rst
+++ b/doc/build/documentation.rst
@@ -16,6 +16,8 @@ the following dependencies are needed to build the documentation:
 
 * texinfo (if building the `Infodoc documentation`_)
 
+* texlive-xetex (if building the `PDF documentation`_ through the *pdfdocs* target)
+
 HTML documentation
 ------------------
 
-- 
2.48.1