add i2c_device_address member to nfc_pn544_device_t

Add I2C slave address. Multiple I2C addresses are possible
for PN544 module. Configure address according to board design.

Change-Id: I847e8f3db631f5039cf15143a9982f4b9b209f27

include/hardware/nfc.h

@@ -76,6 +76,11 @@ typedef struct {
      * Set to 0 to disable the workaround, 1 to enable it.
      */
     uint8_t enable_i2c_workaround;
+    /* I2C slave address. Multiple I2C addresses are
+     * possible for PN544 module. Configure address according to
+     * board design.
+     */
+    uint8_t i2c_device_address;
 } nfc_pn544_device_t;
 
 static inline int nfc_pn544_open(const struct hw_module_t* module,

modules/nfc/nfc_hw_example.c

@@ -44,6 +44,7 @@ static int nfc_open(const hw_module_t* module, const char* name,
         dev->linktype = PN544_LINK_TYPE_INVALID;
         dev->device_node = NULL;
         dev->enable_i2c_workaround = 0;
+        dev->i2c_device_address = 0;
 
         *device = (hw_device_t*) dev;
         return 0;