Add an 'efivars: ' printk prefix to make the log entries stand out more,
for example:

	efivars: Registered efivars operations

While at it, change the sole remaining direct printk() call to pr_err().

Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
---
 drivers/firmware/efi/vars.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/efi/vars.c b/drivers/firmware/efi/vars.c
index aa5ba38f81ff..f34e7741e0c3 100644
--- a/drivers/firmware/efi/vars.c
+++ b/drivers/firmware/efi/vars.c
@@ -6,6 +6,8 @@
  * Copyright (C) 2004 Intel Corporation <matthew.e.tolentino@intel.com>
  */
 
+#define pr_fmt(fmt) "efivars: " fmt
+
 #include <linux/types.h>
 #include <linux/sizes.h>
 #include <linux/errno.h>
@@ -90,7 +92,7 @@ int efivars_unregister(struct efivars *efivars)
 		return -EINTR;
 
 	if (!__efivars) {
-		printk(KERN_ERR "efivars not registered\n");
+		pr_err("efivars not registered\n");
 		rv = -EINVAL;
 		goto out;
 	}
-- 
2.38.2