psa: Fix unused variable warnings

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/library/psa_crypto_driver_wrappers.c b/library/psa_crypto_driver_wrappers.c
index f7240ce..7ba2450 100644
--- a/library/psa_crypto_driver_wrappers.c
+++ b/library/psa_crypto_driver_wrappers.c
@@ -964,6 +964,7 @@
         default:
             /* Key is declared with a lifetime not known to us */
             (void)status;
+            (void)operation;
             (void)key_buffer;
             (void)key_buffer_size;
             (void)alg;
@@ -1035,6 +1036,7 @@
         default:
             /* Key is declared with a lifetime not known to us */
             (void)status;
+            (void)operation;
             (void)key_buffer;
             (void)key_buffer_size;
             (void)alg;
@@ -1606,6 +1608,7 @@
         default:
             /* Key is declared with a lifetime not known to us */
             (void) status;
+            (void) operation;
             (void) key_buffer;
             (void) key_buffer_size;
             (void) alg;
@@ -1677,6 +1680,7 @@
         default:
             /* Key is declared with a lifetime not known to us */
             (void) status;
+            (void) operation;
             (void) key_buffer;
             (void) key_buffer_size;
             (void) alg;