[dif uart] Use matching defines for bit definitions

Signed-off-by: Philipp Wagner <phw@lowrisc.org>
diff --git a/sw/device/tests/dif/dif_uart_unittest.cc b/sw/device/tests/dif/dif_uart_unittest.cc
index d63863d..a8ce5cc 100644
--- a/sw/device/tests/dif/dif_uart_unittest.cc
+++ b/sw/device/tests/dif/dif_uart_unittest.cc
@@ -628,7 +628,7 @@
 
   // Disable last IRQ.
   EXPECT_MASK32(UART_INTR_ENABLE_REG_OFFSET,
-                {{UART_INTR_STATE_RX_PARITY_ERR, 0x1, false}});
+                {{UART_INTR_ENABLE_RX_PARITY_ERR, 0x1, false}});
 
   result = dif_uart_irq_enable(&dif_uart_, kDifUartInterruptRxParityErr,
                                kDifUartDisable);
@@ -654,7 +654,7 @@
 
   // Force last IRQ.
   EXPECT_MASK32(UART_INTR_TEST_REG_OFFSET,
-                {{UART_INTR_ENABLE_RX_PARITY_ERR, 0x1, true}});
+                {{UART_INTR_TEST_RX_PARITY_ERR, 0x1, true}});
 
   result = dif_uart_irq_force(&dif_uart_, kDifUartInterruptRxParityErr);
   EXPECT_EQ(result, kDifUartOk);