config-symmetric-only.h: Remove obsolete comment

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/configs/config-symmetric-only.h b/configs/config-symmetric-only.h
index 512dd76..d7070b8 100644
--- a/configs/config-symmetric-only.h
+++ b/configs/config-symmetric-only.h
@@ -65,9 +65,6 @@
 #define MBEDTLS_PSA_ITS_FILE_C
 #define MBEDTLS_RIPEMD160_C
 #define MBEDTLS_SHA1_C
-/* The library does not currently support enabling SHA-224 without SHA-256.
- * A future version of the library will have this option disabled
- * by default. */
 #define MBEDTLS_SHA224_C
 #define MBEDTLS_SHA256_C
 #define MBEDTLS_SHA384_C