Revert "Revert "Fix MediaDrm security level APIs""

This reverts commit 3553dfe9da9f1bff6d62f3ea52f71f956a5f429b.

Change-Id: I162037cfe692a0b0d277c562fc3f92d48f9446c3
diff --git a/headers/media_plugin/media/drm/DrmAPI.h b/headers/media_plugin/media/drm/DrmAPI.h
index 0a3a356..c44a1f6 100644
--- a/headers/media_plugin/media/drm/DrmAPI.h
+++ b/headers/media_plugin/media/drm/DrmAPI.h
@@ -148,6 +148,9 @@
         enum SecurityLevel {
             // Failure to access security level, an error occurred
             kSecurityLevelUnknown,
+            // The maximum security level of the device. This is the default when
+            // a session is opened if no security level is specified
+            kSecurityLevelMax,
             // Software-based whitebox crypto
             kSecurityLevelSwSecureCrypto,
             // Software-based whitebox crypto and an obfuscated decoder