[S390] tape: Add pr_fmt() macro to all tape source files

Without defining the pr_fmt() macro, the "tape: " prefix will not be
printed when using the pr_xxx printk macros. This patch adds the
missing definitions.

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/char/tape_core.c b/drivers/s390/char/tape_core.c
index f5d6802..81b094e 100644
--- a/drivers/s390/char/tape_core.c
+++ b/drivers/s390/char/tape_core.c
@@ -12,6 +12,8 @@
  */
 
 #define KMSG_COMPONENT "tape"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
 #include <linux/module.h>
 #include <linux/init.h>	     // for kernel parameters
 #include <linux/kmod.h>	     // for requesting modules