Revert "Platform: Remove Musca_A platform code (Deprecation)"

This reverts commit a29d6695749aedb4015320af18e782b85744600a.

Reason for revert: Musca-A is still a reference platform for 1 user.

Change-Id: I3a96d5157677390360aaa82eac96b9810db58c43
diff --git a/docs/getting_started/tfm_secure_boot.rst b/docs/getting_started/tfm_secure_boot.rst
index 60674e4..eeb2cca 100644
--- a/docs/getting_started/tfm_secure_boot.rst
+++ b/docs/getting_started/tfm_secure_boot.rst
@@ -238,6 +238,8 @@
 +---------------------+-----------------+---------------+----------+----------------+--------------+
 | LPC55S69            | Yes             | Yes           | No       | Yes            | No           |
 +---------------------+-----------------+---------------+----------+----------------+--------------+
+| Musca-A             | No              | No            | No       | No             | Yes          |
++---------------------+-----------------+---------------+----------+----------------+--------------+
 | Musca-B1            | Yes             | Yes           | Yes      | Yes            | No           |
 +---------------------+-----------------+---------------+----------+----------------+--------------+
 | Musca-S1            | Yes             | Yes           | Yes      | Yes            | No           |