labs/sysdev-kernel-cross-compiling: use \arch instead of \board

Similarly to the previous commit, use \arch instead of \board to
decide between Image.gz and zImage.

Signed-off-by: Thomas Petazzoni <[email protected]>

Author: tpetazzoni

labs/sysdev-kernel-cross-compiling/sysdev-kernel-cross-compiling.tex

@@ -254,7 +254,7 @@ \section{Load and boot the kernel using U-Boot}
 reset. Reset the board, and customize \code{bootcmd}:
 
 \begin{ubootinput}
-=> setenv bootcmd 'tftp %\zimageboardaddr\ \ifdefstring{\board}{beagleplay}{Image.gz}{zImage}; tftp \dtbboardaddr\ {\dtname}.dtb; \ifdefstring{\arch}{ARM64}{booti}{bootz} \zimageboardaddr\ - \dtbboardaddr'%
+=> setenv bootcmd 'tftp %\zimageboardaddr\ \ifdefstring{\arch}{ARM64}{Image.gz}{zImage}; tftp \dtbboardaddr\ {\dtname}.dtb; \ifdefstring{\arch}{ARM64}{booti}{bootz} \zimageboardaddr\ - \dtbboardaddr'%
 => saveenv
 \end{ubootinput}