labs/kernel-debugging: fix section/subsection

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

labs/kernel-debugging/kernel-debugging.tex

@@ -82,7 +82,7 @@ \subsection{Setup}
 Compile the \code{drvbroken} in this directory, and load it on your
 board. See it crashing in a nice way.
 
-\section{Analyzing the crash message}
+\subsection{Analyzing the crash message}
 
 Analyze the crash message carefully. Knowing that on ARM, the \code{PC}
 register contains the location of the instruction being executed, find
@@ -93,7 +93,7 @@ \section{Analyzing the crash message}
 function. This, with a careful review of the driver source code should
 probably be enough to help you understand and fix the issue.
 
-\section{Locating the exact line where the error happens}
+\subsection{Locating the exact line where the error happens}
 
 Even if you already found out which instruction caused the crash, it's
 useful to use information in the crash report.