Makefile: fix typo in a comment

Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

Makefile

@@ -577,7 +577,7 @@ ifeq ($(BR2_TOOLCHAIN_HAS_THREADS),y)
 endif
 
 	mkdir -p $(TARGET_DIR)/etc
-	# Mandatory configuration file and auxilliary cache directory
+	# Mandatory configuration file and auxiliary cache directory
 	# for recent versions of ldconfig
 	touch $(TARGET_DIR)/etc/ld.so.conf
 	mkdir -p $(TARGET_DIR)/var/cache/ldconfig