[S390] vmcp cleanup

A number of small changes to vmcp:
 - Change preferred email address.
 - Use PRINT_xxx machros from debug.h like most s390 drivers, define
   "vmcp:" as PRINTK_HEADER and wrap error message at column 80.
 - Add error number to error message.
 - Update copyright, as I touched this file.
 - Small whitespace diff.
 - Use mutex instead of semaphore (Thanks Heiko for the patch)
 - Don't register debug feature on failure.
 - Check debug feature registration on init to avoid a potential oops
   on unload if the debug feature could not be registered--> 2 more
   messages.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/char/vmcp.h b/drivers/s390/char/vmcp.h
index 8a5975f..6a99394 100644
--- a/drivers/s390/char/vmcp.h
+++ b/drivers/s390/char/vmcp.h
@@ -12,8 +12,8 @@
  * The idea of this driver is based on cpint from Neale Ferguson
  */
 
-#include <asm/semaphore.h>
 #include <linux/ioctl.h>
+#include <linux/mutex.h>
 
 #define VMCP_GETCODE _IOR(0x10, 1, int)
 #define VMCP_SETBUF _IOW(0x10, 2, int)
@@ -26,5 +26,5 @@
 	int resp_code;
 	/* As we use copy_from/to_user, which might     *
 	 * sleep and cannot use a spinlock              */
-	struct semaphore mutex;
+	struct mutex mutex;
 };