[DeviceDrivers] Add more baud rate in serial.

components/drivers/include/drivers/serial.h

@@ -33,12 +33,15 @@
 #define BAUD_RATE_2400                  2400
 #define BAUD_RATE_4800                  4800
 #define BAUD_RATE_9600                  9600
+#define BAUD_RATE_19200                 19200
 #define BAUD_RATE_38400                 38400
 #define BAUD_RATE_57600                 57600
 #define BAUD_RATE_115200                115200
 #define BAUD_RATE_230400                230400
 #define BAUD_RATE_460800                460800
 #define BAUD_RATE_921600                921600
+#define BAUD_RATE_2000000               2000000
+#define BAUD_RATE_3000000               3000000
 
 #define DATA_BITS_5                     5
 #define DATA_BITS_6                     6