Update device.h

Activated the I2CSlave functions. Slave block read/write operations are fully supported. The slave byte read and writes need general modification to I2CSlave.cpp. See pending Issue.
Activated the PWM functions. They are supported now using the SCT after updating us_ticker() to use the MRT instead of the SCT.

Author: Willem23

libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC81X/device.h

@@ -29,7 +29,7 @@
 #define DEVICE_SERIAL_FC        1
 
 #define DEVICE_I2C              1
-#define DEVICE_I2CSLAVE         0
+#define DEVICE_I2CSLAVE         1
 
 #define DEVICE_SPI              1
 #define DEVICE_SPISLAVE         1
@@ -40,7 +40,7 @@
 
 #define DEVICE_ETHERNET         0
 
-#define DEVICE_PWMOUT           0
+#define DEVICE_PWMOUT           1
 
 #define DEVICE_SEMIHOST         0
 #define DEVICE_LOCALFILESYSTEM  0