board/freescale/common: secure_boot: Set bootdelay to -2.

Uboot prompt must not be available while running
secure boot. TO ensure this  bootdelay must be set
to -2.

Signed-off-by: Udit Agarwal <udit.agarwal@nxp.com>
Reviewed-by: Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com>
diff --git a/board/freescale/common/fsl_chain_of_trust.c b/board/freescale/common/fsl_chain_of_trust.c
index 97376c4..dddfd26 100644
--- a/board/freescale/common/fsl_chain_of_trust.c
+++ b/board/freescale/common/fsl_chain_of_trust.c
@@ -79,7 +79,7 @@
 	 * bootdelay = 0 (To disable Boot Prompt)
 	 * bootcmd = CONFIG_CHAIN_BOOT_CMD (Validate and execute Boot script)
 	 */
-	env_set("bootdelay", "0");
+	env_set("bootdelay", "-2");
 
 #ifdef CONFIG_ARM
 	env_set("secureboot", "y");