fastboot: Add help message for continue command

Change-Id: I578b1b7c2d74d09d44ce9100bfe582aaa25c31b1
Signed-off-by: Bruce Beare <bruce.j.beare@intel.com>
diff --git a/fastboot/fastboot.c b/fastboot/fastboot.c
index f3bfbeba..14048a1 100644
--- a/fastboot/fastboot.c
+++ b/fastboot/fastboot.c
@@ -223,6 +223,7 @@
             "  boot <kernel> [ <ramdisk> ]              download and boot kernel\n"
             "  flash:raw boot <kernel> [ <ramdisk> ]    create bootimage and flash it\n"
             "  devices                                  list all connected devices\n"
+            "  continue                                 continue with autoboot\n"
             "  reboot                                   reboot device normally\n"
             "  reboot-bootloader                        reboot device into bootloader\n"
             "\n"