freescale/layerscape: Rename the config CONFIG_SECURE_BOOT name

Rename CONFIG_SECURE_BOOT to CONFIG_NXP_ESBC to avoid conflict
with UEFI secure boot.

Signed-off-by: Udit Agarwal <udit.agarwal@nxp.com>
Signed-off-by: Priyanka Jain <priyanka.jain@nxp.com>
diff --git a/board/freescale/common/Kconfig b/board/freescale/common/Kconfig
index 8b89c10..1b1fd69 100644
--- a/board/freescale/common/Kconfig
+++ b/board/freescale/common/Kconfig
@@ -1,5 +1,5 @@
 config CHAIN_OF_TRUST
-	depends on !FIT_SIGNATURE && SECURE_BOOT
+	depends on !FIT_SIGNATURE && NXP_ESBC
 	imply CMD_BLOB
 	imply CMD_HASH if ARM
 	select FSL_CAAM