Boot time labs: simplify git instructions

- No need for gitk
- No need for creating commits

Signed-off-by: Michael Opdenacker <michael.opdenacker@bootlin.com>

labs/boot-time-build-kernel-and-start-system/boot-time-build-kernel-and-start-system.tex

@@ -33,14 +33,11 @@ \section{Setup}
 First, open the \code{Makefile} file just to check the Linux kernel
 version that you currently have.
 
-Now, let's create a local branch starting from that remote branch:
+Now, let's check out the \code{5.11.y} branch:
 \begin{verbatim}
-git checkout -b 5.11-beaglecam stable/linux-5.11.y
+git checkout stable/linux-5.11.y
 \end{verbatim}
 
-This local branch will allow us to keep our modifications to the Linux
-kernel to support the 4.3" LCD cape that we're using.
-
 Open \code{Makefile} again and make sure you now have a 5.11.<n> version.
 
 \section{Compiling environment}

labs/boot-time-sources-download/boot-time-sources-download.tex

@@ -2,7 +2,7 @@
 code}{Save time and start fetching the source code that you will need
 during these labs}
 
-\section{Installing git packages}
+\section{Installing the git package}
 
 We are going to access bootloader, kernel and Buildroot sources through
 their \code{git} repositories, which will allow us to track any changes
@@ -12,26 +12,12 @@ \section{Installing git packages}
 share it), fetching such sources is likely to take a significant amount
 of time. That's why we're starting such downloads now.
 
-So, let's install the below packages:
+So, let's install the below package:
 
 \begin{verbatim}
-sudo apt install git gitk git-email
+sudo apt install git
 \end{verbatim}
 
-\section{Git configuration}
-
-After installing \code{git} on a new machine, the first thing to do is
-to let \code{git} know about your name and e-mail address:
-
-\begin{verbatim}
-git config --global user.name 'My Name'
-git config --global user.email me@mydomain.net
-\end{verbatim}
-
-Such information will be stored in commits. It is important
-to configure it properly in case we need to generate and
-send patches.
-
 \section{Cloning the Buildroot source tree}
 
 Go to the \code{$HOME/boot-time-labs/rootfs} directory.