gpio: mockup: use pr_fmt()

We don't need a custom logging helper. Let's use the standard pr_fmt()
macro which allows us to use all pr_*() routines with custom format.
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

drivers/gpio/gpio-mockup.c

@@ -7,6 +7,8 @@
  * Copyright (C) 2017 Bartosz Golaszewski <brgl@bgdev.pl>
  */
 
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
 #include <linux/debugfs.h>
 #include <linux/gpio/driver.h>
 #include <linux/interrupt.h>
@@ -30,8 +32,6 @@
 /* Maximum of three properties + the sentinel. */
 #define GPIO_MOCKUP_MAX_PROP	4
 
-#define gpio_mockup_err(...)	pr_err(KBUILD_MODNAME ": " __VA_ARGS__)
-
 /*
  * struct gpio_pin_status - structure describing a GPIO status
  * @dir:       Configures direction of gpio as "in" or "out"
@@ -548,7 +548,7 @@ static int __init gpio_mockup_init(void)
 
 	err = platform_driver_register(&gpio_mockup_driver);
 	if (err) {
-		gpio_mockup_err("error registering platform driver\n");
+		pr_err("error registering platform driver\n");
 		debugfs_remove_recursive(gpio_mockup_dbg_dir);
 		return err;
 	}
@@ -577,7 +577,7 @@ static int __init gpio_mockup_init(void)
 
 		pdev = platform_device_register_full(&pdevinfo);
 		if (IS_ERR(pdev)) {
-			gpio_mockup_err("error registering device");
+			pr_err("error registering device");
 			platform_driver_unregister(&gpio_mockup_driver);
 			gpio_mockup_unregister_pdevs();
 			debugfs_remove_recursive(gpio_mockup_dbg_dir);