fix(security): correct AM62L removing R5 SPL reference

Correct existing diagram showing R5 SPL for AM62L as well.
Add reference to fTPM based secure storage guide.

Signed-off-by: Shiva Tripathi <s-tripathi1@ti.com>

Author: shiva-ti

source/images/Auth_default_bootflow_AM62L.png

@@ -71,12 +71,16 @@ Before encrypting a drive, it is recommended to perform a secure erase by overwr
 Setup
 *****
 
-.. Image:: /images/Auth_default_bootflow.png
-     :align: center
+.. ifconfig:: CONFIG_part_variant not in ('AM62LX')
 
-.. note::
+    .. Image:: /images/Auth_default_bootflow.png
+        :align: center
+
+.. ifconfig:: CONFIG_part_variant in ('AM62LX')
+
+    .. Image:: /images/Auth_default_bootflow_AM62L.png
+        :align: center
 
-   A new Yocto layer is in the works to automate all of the below steps
 
 The following steps describe how to build user-space tools and configuration on Yocto. Please use :ref:`Processor SDK - Building the SDK with Yocto <building-the-sdk-with-yocto>` as reference.
 
@@ -240,14 +244,21 @@ The following steps describe how to build user-space tools and configuration on
 
 #. Repackage the initramfs into the kernel, build and replace the :file:`root/boot/Image` and boot.
 
-.. Image:: /images/Auth_secure_bootflow.png
-     :align: center
+.. ifconfig:: CONFIG_part_variant not in ('AM62LX')
+
+    .. Image:: /images/Auth_secure_bootflow.png
+        :align: center
+
+.. ifconfig:: CONFIG_part_variant in ('AM62LX')
+
+    .. Image:: /images/Auth_secure_bootflow_AM62L.png
+        :align: center
 
 **********
 Next steps
 **********
 
-This guide showcases the authenticated boot flow on TI devices and is not meant to be directly used in production. The demo utilizes a pass_key to secure the encrypted partition and is placed in the initramfs in a non-secure manner.
+This guide showcases the authenticated boot flow on TI devices and is not meant to be directly used in production. The demo utilizes a pass_key to secure the encrypted partition and is placed in the initramfs in a non-secure manner. Refer :ref:`File System Encryption with fTPM <filesystem-encryption>` for details on using fTPM based key sealing and secure storage of keys. 
 
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 See Also