Boot time slides: fix typo

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

slides/boot-time-toolchain2/boot-time-toolchain2.tex

@@ -49,5 +49,5 @@
     with binaries relying on shared libraries.
 \end{itemize}
 Switching to {\em Musl} as it is supposed to allow for smaller static
-binariess, which will be useful in later labs.
+binaries, which will be useful in later labs.
 \end{frame}