feat(fvp): add Event Log maximum size property in DT

Updated the code to get and set the 'tpm_event_log_max_size' property
in the event_log.dtsi.

In this change, the maximum Event Log buffer size allocated by BL1 is
passed to BL2, rather than both relying on the maximum Event Log buffer
size macro.

Change-Id: I7aa6256390872171e362b6f166f3f7335aa6e425
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
diff --git a/docs/components/measured_boot/event_log.rst b/docs/components/measured_boot/event_log.rst
index 0881248..c102bea 100644
--- a/docs/components/measured_boot/event_log.rst
+++ b/docs/components/measured_boot/event_log.rst
@@ -33,3 +33,11 @@
 - tpm_event_log_size [mandatory]
     - value type: <u32>
     - Event Log size.
+
+- tpm_event_log_max_size [mandatory]
+    - value type: <u32>
+    - Event Log maximum size.
+
+--------------
+
+*Copyright (c) 2023, Arm Limited and Contributors. All rights reserved.*