Return right error code.
Issue : 126
https://github.com/ARMmbed/mbed-crypto/issues/126
PSA_ERROR_BUFFER_TOO_SMALL error returned when we check for output_size.
diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index 3c31872..f631d83 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -2755,7 +2755,7 @@
mbedtls_rsa_context *rsa = slot->data.rsa;
int ret;
if( output_size < mbedtls_rsa_get_len( rsa ) )
- return( PSA_ERROR_INVALID_ARGUMENT );
+ return( PSA_ERROR_BUFFER_TOO_SMALL );
#if defined(MBEDTLS_PKCS1_V15)
if( alg == PSA_ALG_RSA_PKCS1V15_CRYPT )
{