Add ChangeLog entry

Signed-off-by: Janos Follath <janos.follath@arm.com>

ChangeLog.d/rsa-fix-priviliged-side-channel.txt

@@ -0,0 +1,8 @@
+Security
+   * An adversary with access to precise enough information about memory
+     accesses (typically, an untrusted operating system attacking a secure
+     enclave) could recover an RSA private key after observing the victim
+     performing a single private-key operation if the window size used for the
+     exponentiation was 3 or smaller. Found and reported by Zili KOU,
+     Wenjian HE, Sharad Sinha, and Wei ZHANG.
+