Add implementation of psa_crypto_input_copy_free()

Signed-off-by: David Horstmann <david.horstmann@arm.com>
diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index b828e99..d4c566d 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -5584,4 +5584,11 @@
     return status;
 }
 
+void psa_crypto_input_copy_free(psa_crypto_input_copy_t *input_copy)
+{
+    mbedtls_free(input_copy->buffer);
+    input_copy->buffer = NULL;
+    input_copy->len = 0;
+}
+
 #endif /* MBEDTLS_PSA_CRYPTO_C */