Fix incorrect PSA key usage

Signed-off-by: Paul Elliott <paul.elliott@arm.com>
diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index 6598cf4..a6d0cdb 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -3227,7 +3227,7 @@
         return( PSA_ERROR_NOT_SUPPORTED );
 
     status = psa_get_and_lock_key_slot_with_policy(
-                 key, &slot, PSA_KEY_USAGE_DECRYPT, alg );
+                 key, &slot, PSA_KEY_USAGE_ENCRYPT, alg );
 
     if( status != PSA_SUCCESS )
     {