esp8266/modpybuart: Fix UART parity setting.

The configuration bits for the UART register were wrong and the parity
couldn't be enabled, because the exist_parity member hasn't been updated. I
took this ESP8266 register description (http://esp8266.ru/esp8266-uart-reg/)
as reference.

Verification has been done with a logic analyzer.
diff --git a/esp8266/uart.h b/esp8266/uart.h
index 21894d3..2b97683 100644
--- a/esp8266/uart.h
+++ b/esp8266/uart.h
@@ -1,6 +1,8 @@
 #ifndef _INCLUDED_UART_H_
 #define _INCLUDED_UART_H_
 
+#include <eagle_soc.h>
+
 #define UART0 (0)
 #define UART1 (1)
 
@@ -18,14 +20,14 @@
 } UartStopBitsNum;
 
 typedef enum {
-    UART_NONE_BITS = 0,
-    UART_ODD_BITS   = 0,
-    UART_EVEN_BITS = BIT4
+    UART_NONE_BITS  = 0,
+    UART_ODD_BITS   = BIT0,
+    UART_EVEN_BITS  = 0
 } UartParityMode;
 
 typedef enum {
     UART_STICK_PARITY_DIS   = 0,
-    UART_STICK_PARITY_EN    = BIT3 | BIT5
+    UART_STICK_PARITY_EN    = BIT1
 } UartExistParity;
 
 typedef enum {