[cryptotest] Allow longer RSA signatures

Some tests in the wycheproof test vector set are error tests. In one
of these error tests, a larger signature (514 instead of 512-bytes) is
sent to the DUT. However, we currently limit the signature payload to 512-
bytes, letting the test fail.

The solution to this is simple, increase the max. number of signature bytes
to 512-bytes. The CL now gets this 514-byte signature and internally fails,
as expected by the test.

Signed-off-by: Pascal Nasahl <[email protected]>
(cherry picked from commit 9ab2711)

Author: nasahlpa

sw/device/tests/crypto/cryptotest/json/rsa_commands.h

@@ -13,7 +13,10 @@ extern "C" {
 
 #define RSA_CMD_MAX_MESSAGE_BYTES 512
 #define RSA_CMD_MAX_N_BYTES 512
-#define RSA_CMD_MAX_SIGNATURE_BYTES 512
+// There are some error test cases that send larger signatures than 512 bytes.
+// The cryptolib should detect this and abort with an error.
+// Accomodate for these additional bytes.
+#define RSA_CMD_MAX_SIGNATURE_BYTES 514
 
 // clang-format off