s390/pci: reshuffle struct used to write debug data

zpci_err_insn writes stale stack content to the debugfs.

Ensure that the struct in zpci_err_insn is ordered in a way that
we don't have uninitialized holes in it. In addition to that
add the packed attribute.

Fixes: 3d8258e4 (s390/pci: move debug messages to debugfs)
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/pci/pci_insn.c

@@ -16,11 +16,11 @@
 static inline void zpci_err_insn(u8 cc, u8 status, u64 req, u64 offset)
 {
 	struct {
-		u8 cc;
-		u8 status;
 		u64 req;
 		u64 offset;
-	} data = {cc, status, req, offset};
+		u8 cc;
+		u8 status;
+	} __packed data = {req, offset, cc, status};
 
 	zpci_err_hex(&data, sizeof(data));
 }