[S390] tape: Compression overwrites crypto setting

After switching compression on/off with the mt command, tape encryption is no
longer working. The reason for that is, that the modeset_byte is set to
the compression value instead of using bitwise and/or bit operations to
enable/disable the corresponding bit.
Signed-off-by: Michael Holzheu <holzheu@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/char/tape_std.c

@@ -647,7 +647,10 @@ tape_std_mtcompression(struct tape_device *device, int mt_count)
 		return PTR_ERR(request);
 	request->op = TO_NOP;
 	/* setup ccws */
-	*device->modeset_byte = (mt_count == 0) ? 0x00 : 0x08;
+	if (mt_count == 0)
+		*device->modeset_byte &= ~0x08;
+	else
+		*device->modeset_byte |= 0x08;
 	tape_ccw_cc(request->cpaddr, MODE_SET_DB, 1, device->modeset_byte);
 	tape_ccw_end(request->cpaddr + 1, NOP, 0, NULL);
 	/* execute it */