Calculate hashes of ssl encryption and decryption keys

Optimize the key switching mechanism to set the key only if 
a different operation is performed with the context.
Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
diff --git a/scripts/config.pl b/scripts/config.pl
index 5d2b28e..1c3422e 100755
--- a/scripts/config.pl
+++ b/scripts/config.pl
@@ -58,6 +58,7 @@
 #   MBEDTLS_AES_SCA_COUNTERMEASURES
 #   MBEDTLS_CTR_DRBG_USE_128_BIT_KEY
 #   MBEDTLS_SSL_TRANSFORM_OPTIMIZE_CIPHERS
+#   MBEDTLS_VALIDATE_SSL_KEYS_INTEGRITY
 #   and any symbol beginning _ALT
 #
 # The baremetal configuration excludes options that require a library or
@@ -142,6 +143,7 @@
 MBEDTLS_AES_SCA_COUNTERMEASURES
 MBEDTLS_CTR_DRBG_USE_128_BIT_KEY
 MBEDTLS_SSL_TRANSFORM_OPTIMIZE_CIPHERS
+MBEDTLS_VALIDATE_SSL_KEYS_INTEGRITY
 _ALT\s*$
 );