distro_bootcmd: Fix copy-paste error

The "SCRIPT FAILED" string is copied from scan_dev_for_scripts script,
update it so it prints "EXTLINUX FAILED" instead in scan_dev_for_extlinux
script.

Signed-off-by: Marek Vasut <marex@denx.de>

include/config_distro_bootcmd.h

@@ -484,7 +484,7 @@
 				"${prefix}${boot_syslinux_conf}; then "   \
 			"echo Found ${prefix}${boot_syslinux_conf}; "     \
 			"run boot_extlinux; "                             \
-			"echo SCRIPT FAILED: continuing...; "             \
+			"echo EXTLINUX FAILED: continuing...; "           \
 		"fi\0"                                                    \
 	\
 	"boot_a_script="                                                  \