Add Changelog for driver-only ECC so far

Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
diff --git a/ChangeLog.d/driver-only-ecdh.txt b/ChangeLog.d/driver-only-ecc.txt
similarity index 65%
rename from ChangeLog.d/driver-only-ecdh.txt
rename to ChangeLog.d/driver-only-ecc.txt
index 1aeed64..ca23db9 100644
--- a/ChangeLog.d/driver-only-ecdh.txt
+++ b/ChangeLog.d/driver-only-ecc.txt
@@ -5,3 +5,6 @@
      MBEDTLS_USE_PSA_CRYPTO. Restartable/interruptible ECDHE operations in
      TLS 1.2 (ECDHE-ECDSA key exchange) are not supported in those builds yet,
      as PSA does not have an API for restartable ECDH yet.
+   * When all of ECDH, ECDSA and EC J-PAKE are either disabled or provided by
+     a driver, it is possible to disable MBEDTLS_ECP_C and still get support
+     for ECC keys and algorithms in PSA. See docs/driver-only-builds.txt.