Documentation/arm/sa1100/assabet: Fix 'make assabet_defconfig' command

"make assabet_config" doesn't work.
Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/arm/sa1100/assabet.rst

@@ -14,7 +14,7 @@ Building the kernel
 
 To build the kernel with current defaults::
 
-	make assabet_config
+	make assabet_defconfig
 	make oldconfig
 	make zImage