Fix parity test

Apparently Parity is not reliable and Framing is
thrown depending on the hardware instead.

Author: Sh3Rm4n

testsuite/tests/uart.rs

@@ -240,7 +240,9 @@ mod tests {
 
         unwrap!(nb::block!(serial_odd.write(b'x')));
         let result = nb::block!(serial_even.read());
-        assert!(matches!(result, Err(Error::Parity)));
+        // Note: I'm not really sure in what case Framing is thrown but not Parity
+        // but it happens
+        assert!(matches!(result, Err(Error::Parity | Error::Framing)));
 
         // Finally restore serial devices in state.
         let (usart_slow, pins_slow) = serial_even.free();