rtc: rtc-efi: use dev_err()/dev_warn()/pr_err() instead of printk()

Fix the checkpatch warnings as below:

  WARNING: Prefer netdev_err(netdev, ... then dev_err(dev, ... then pr_err(...  to printk(KERN_ERR ...
  WARNING: please, no space before tabs
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/rtc-efi.c

@@ -13,6 +13,8 @@
  *
  */
 
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/time.h>
@@ -47,7 +49,7 @@ compute_wday(efi_time_t *eft)
 	int ndays = 0;
 
 	if (eft->year < 1998) {
-		printk(KERN_ERR "efirtc: EFI year < 1998, invalid date\n");
+		pr_err("EFI year < 1998, invalid date\n");
 		return -1;
 	}
 
@@ -142,7 +144,7 @@ static int efi_set_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
 	 */
 	status = efi.set_wakeup_time((efi_bool_t)wkalrm->enabled, &eft);
 
-	printk(KERN_WARNING "write status is %d\n", (int)status);
+	dev_warn(dev, "write status is %d\n", (int)status);
 
 	return status == EFI_SUCCESS ? 0 : -EINVAL;
 }
@@ -157,7 +159,7 @@ static int efi_read_time(struct device *dev, struct rtc_time *tm)
 
 	if (status != EFI_SUCCESS) {
 		/* should never happen */
-		printk(KERN_ERR "efitime: can't read time\n");
+		dev_err(dev, "can't read time\n");
 		return -EINVAL;
 	}