Rename generator functions to psa_key_derivation_xxx

Generators are mostly about key derivation (currently: only about key
derivation). "Generator" is not a commonly used term in cryptography.
So favor "derivation" as terminology. Call a generator a key
derivation operation structure, since it behaves like other multipart
operation structures. Furthermore, the function names are not fully
consistent.

In this commit, I rename the functions to consistently have the prefix
"psa_key_derivation_". I used the following command:

    perl -i -pe '%t = (
        psa_crypto_generator_t => "psa_key_derivation_operation_t",
        psa_crypto_generator_init => "psa_key_derivation_init",
        psa_key_derivation_setup => "psa_key_derivation_setup",
        psa_key_derivation_input_key => "psa_key_derivation_input_key",
        psa_key_derivation_input_bytes => "psa_key_derivation_input_bytes",
        psa_key_agreement => "psa_key_derivation_key_agreement",
        psa_set_generator_capacity => "psa_key_derivation_set_capacity",
        psa_get_generator_capacity => "psa_key_derivation_get_capacity",
        psa_generator_read => "psa_key_derivation_output_bytes",
        psa_generate_derived_key => "psa_key_derivation_output_key",
        psa_generator_abort => "psa_key_derivation_abort",
        PSA_CRYPTO_GENERATOR_INIT => "PSA_KEY_DERIVATION_OPERATION_INIT",
        PSA_GENERATOR_UNBRIDLED_CAPACITY => "PSA_KEY_DERIVATION_UNLIMITED_CAPACITY",
        ); s/\b(@{[join("|", keys %t)]})\b/$t{$1}/ge' $(git ls-files)
diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index 81c69dd..41c2bd2 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -3116,7 +3116,7 @@
         unsigned char *own_pubkey_ecpoint;
         size_t own_pubkey_ecpoint_len;
 
-        psa_crypto_generator_t generator = PSA_CRYPTO_GENERATOR_INIT;
+        psa_key_derivation_operation_t generator = PSA_KEY_DERIVATION_OPERATION_INIT;
 
         header_len = 4;
 
@@ -3178,7 +3178,7 @@
         content_len = own_pubkey_ecpoint_len + 1;
 
         /* Compute ECDH shared secret. */
-        status = psa_key_agreement( &generator,
+        status = psa_key_derivation_key_agreement( &generator,
                                     handshake->ecdh_psa_privkey,
                                     handshake->ecdh_psa_peerkey,
                                     handshake->ecdh_psa_peerkey_len,
@@ -3191,16 +3191,16 @@
         ssl->handshake->pmslen =
             MBEDTLS_PSA_ECC_KEY_BYTES_OF_CURVE( handshake->ecdh_psa_curve );
 
-        status = psa_generator_read( &generator,
+        status = psa_key_derivation_output_bytes( &generator,
                                      ssl->handshake->premaster,
                                      ssl->handshake->pmslen );
         if( status != PSA_SUCCESS )
         {
-            psa_generator_abort( &generator );
+            psa_key_derivation_abort( &generator );
             return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED );
         }
 
-        status = psa_generator_abort( &generator );
+        status = psa_key_derivation_abort( &generator );
         if( status != PSA_SUCCESS )
             return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED );