Use MBEDTLS_PK_SIGNATURE_MAX_SIZE in pkey sample programs
Use the constant that is now provided by the crypto submodule instead
of rolling our own definition which is not correct in all cases.
diff --git a/programs/pkey/pk_verify.c b/programs/pkey/pk_verify.c
index a6bfe3f..72caf71 100644
--- a/programs/pkey/pk_verify.c
+++ b/programs/pkey/pk_verify.c
@@ -65,7 +65,7 @@
size_t i;
mbedtls_pk_context pk;
unsigned char hash[32];
- unsigned char buf[MBEDTLS_MPI_MAX_SIZE];
+ unsigned char buf[MBEDTLS_PK_SIGNATURE_MAX_SIZE];
char filename[512];
mbedtls_pk_init( &pk );