UBI: use pr_ helper instead of printk

Use 'pr_err()' instead of 'printk(KERN_ERR', etc.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
diff --git a/drivers/mtd/ubi/gluebi.c b/drivers/mtd/ubi/gluebi.c
index c25aa29..4bd4db8 100644
--- a/drivers/mtd/ubi/gluebi.c
+++ b/drivers/mtd/ubi/gluebi.c
@@ -41,7 +41,7 @@
 #include "ubi-media.h"
 
 #define err_msg(fmt, ...)                                   \
-	printk(KERN_DEBUG "gluebi (pid %d): %s: " fmt "\n", \
+	pr_err("gluebi (pid %d): %s: " fmt "\n",            \
 	       current->pid, __func__, ##__VA_ARGS__)
 
 /**