x230: external_install_bottom.sh: fix usage text

x230/external_install_bottom.sh

@@ -23,10 +23,10 @@ usage()
 	echo "  connected to the X230's bottom chip (farther away from"
 	echo "  the display, closer to you)."
 	echo ""
-	echo "Usage: $0 [-c <chipname>] [-a] [-m] [-k <backup_filename>] [-l]"
+	echo "Usage: $0 [-m] [-k <backup_filename>] [-l] [-f <flasher>] [-b <spispeed>] [-c <chip>]"
 	echo ""
 	echo " -f <hardware_flasher>   supported flashers: rpi, ch341a"
-	echo " -c <chipname>           flashrom chip description to use"
+	echo " -c <chipname>           flashrom chip name to use"
 	echo " -m                      apply me_cleaner -S -d"
 	echo " -l                      lock the flash instead of unlocking it"
 	echo " -k <backup>             save the current image as"