NFC: digital: digital_in_send_attrib_req() can be static

CC: "Mark A. Greer" <mgreer@animalcreek.com>
CC: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

net/nfc/digital_technology.c

@@ -613,7 +613,7 @@ exit:
 		digital_poll_next_tech(ddev);
 }
 
-int digital_in_send_attrib_req(struct nfc_digital_dev *ddev,
+static int digital_in_send_attrib_req(struct nfc_digital_dev *ddev,
 			       struct nfc_target *target,
 			       struct digital_sensb_res *sensb_res)
 {