staging/frontier: fix checkpatch warnings

The below checkpatch warns was fixed,

drivers/staging/frontier/tranzport.c:356: WARNING: Prefer pr_err(... to printk(KERN_ERR, ...
drivers/staging/frontier/tranzport.c:523: WARNING: Prefer pr_err(... to printk(KERN_ERR, ...
drivers/staging/frontier/tranzport.c:696: WARNING: Prefer pr_err(... to printk(KERN_ERR, ...
drivers/staging/frontier/alphatrack.c:336: WARNING: Prefer pr_err(... to printk(KERN_ERR, ...
drivers/staging/frontier/alphatrack.c:497: WARNING: Prefer pr_err(... to printk(KERN_ERR, ...
drivers/staging/frontier/alphatrack.c:568: WARNING: Prefer pr_err(... to printk(KERN_ERR, ...
Signed-off-by: Toshiaki Yamane <yamanetoshi@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/frontier/alphatrack.c

@@ -333,7 +333,7 @@ static int usb_alphatrack_open(struct inode *inode, struct file *file)
 	interface = usb_find_interface(&usb_alphatrack_driver, subminor);
 
 	if (!interface) {
-		printk(KERN_ERR "%s - error, can't find device for minor %d\n",
+		pr_err("%s - error, can't find device for minor %d\n",
 		       __func__, subminor);
 		retval = -ENODEV;
 		goto unlock_disconnect_exit;
@@ -494,7 +494,7 @@ static ssize_t usb_alphatrack_read(struct file *file, char __user *buffer,
 	/* verify that the device wasn't unplugged */
 	if (dev->intf == NULL) {
 		retval = -ENODEV;
-		printk(KERN_ERR "%s: No device or device unplugged %d\n",
+		pr_err("%s: No device or device unplugged %d\n",
 		       __func__, retval);
 		goto unlock_exit;
 	}
@@ -565,7 +565,7 @@ static ssize_t usb_alphatrack_write(struct file *file,
 	/* verify that the device wasn't unplugged */
 	if (dev->intf == NULL) {
 		retval = -ENODEV;
-		printk(KERN_ERR "%s: No device or device unplugged %d\n",
+		pr_err("%s: No device or device unplugged %d\n",
 		       __func__, retval);
 		goto unlock_exit;
 	}

drivers/staging/frontier/tranzport.c

@@ -353,8 +353,8 @@ static int usb_tranzport_open(struct inode *inode, struct file *file)
 	interface = usb_find_interface(&usb_tranzport_driver, subminor);
 
 	if (!interface) {
-		printk(KERN_ERR "%s - error, can't find device for minor %d\n",
-			__func__, subminor);
+		pr_err("%s - error, can't find device for minor %d\n",
+		       __func__, subminor);
 		retval = -ENODEV;
 		goto unlock_disconnect_exit;
 	}
@@ -520,8 +520,8 @@ static ssize_t usb_tranzport_read(struct file *file, char __user *buffer,
 	/* verify that the device wasn't unplugged */
 	if (dev->intf == NULL) {
 		retval = -ENODEV;
-		printk(KERN_ERR "%s: No device or device unplugged %d\n",
-			__func__, retval);
+		pr_err("%s: No device or device unplugged %d\n",
+		       __func__, retval);
 		goto unlock_exit;
 	}
 
@@ -693,8 +693,8 @@ static ssize_t usb_tranzport_write(struct file *file,
 	/* verify that the device wasn't unplugged */
 	if (dev->intf == NULL) {
 		retval = -ENODEV;
-		printk(KERN_ERR "%s: No device or device unplugged %d\n",
-			__func__, retval);
+		pr_err("%s: No device or device unplugged %d\n",
+		       __func__, retval);
 		goto unlock_exit;
 	}