s390/chpid: make headers usable (again)

Add back a hunk from "4dcc2a4 s390/chsc: make headers usable"
which was lost during the merge of the UAPI patch.

Signed-off-by: Sebastian Ott <[e-mail]>
Signed-off-by: Martin Schwidefsky <[e-mail]>

arch/s390/include/uapi/asm/chpid.h

···
 /*
- *    Copyright IBM Corp. 2007
+ *    Copyright IBM Corp. 2007, 2012
  *    Author(s): Peter Oberparleiter <[e-mail]>
  */
 
···
 #define __MAX_CHPID 255
 
 struct chp_id {
-	u8 reserved1;
-	u8 cssid;
-	u8 reserved2;
-	u8 id;
+	__u8 reserved1;
+	__u8 cssid;
+	__u8 reserved2;
+	__u8 id;
 } __attribute__((packed));