Now, NFC_EVENT_DEVICE_ADDED doesn't send NFC_ATTR_RF_MODE. But
NFC_CMD_GET_DEVICE send.

To get NFC_ATTR_RF_MODE, we have to call NFC_CMD_GET_DEVICE just for
NFC_ATTR_RF_MODE when get NFC_EVENT_DEVICE_ADDED.

This fixes those inconsistent.
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>