NFC: digital: Remove PR_ERR and PR_DBG macros

They can be replaced by the standard pr_err and pr_debug one after
defining the right pr_fmt macro.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/net/nfc/digital_technology.c b/net/nfc/digital_technology.c
index 564735f..5a13e1bb 100644
--- a/net/nfc/digital_technology.c
+++ b/net/nfc/digital_technology.c
@@ -13,6 +13,8 @@
  *
  */
 
+#define pr_fmt(fmt) "digital: %s: " fmt, __func__
+
 #include "digital.h"
 
 #define DIGITAL_CMD_SENS_REQ    0x26
@@ -258,7 +260,7 @@
 
 	skb = digital_skb_alloc(ddev, 2);
 	if (!skb) {
-		PR_ERR("alloc_skb failed");
+		pr_err("alloc_skb failed");
 		return -ENOMEM;
 	}