[kat/rsa] Fix incorrect ordering when comparing RSA-OAEP plaintexts

RSA-OAEP reverses the byte order of its inputs which was not accounted
for which causing unwanted test failures.

Signed-off-by: Andrea Caforio <[email protected]>

Author: andrea-caforio

sw/host/tests/crypto/rsa_kat/src/main.rs

@@ -217,7 +217,7 @@ fn run_rsa_testcase(
                     // Only check plaintext if the response is valid.
                     assert_eq!(
                         rsa_decrypt_resp.plaintext[0..test_case.message.len()],
-                        test_case.message[0..test_case.message.len()]
+                        ptx[0..test_case.message.len()]
                     );
                 }
             }