s390/ipl: ensure loadparm valid flag is set

When loadparm is set in reipl parm block, the kernel should also set
DIAG308_FLAGS_LP_VALID flag.

This fixes loadparm ignoring during z/VM fcp -> ccw reipl and kvm direct
boot -> ccw reipl.

Cc: <stable@vger.kernel.org>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/kernel/ipl.c

@@ -776,6 +776,7 @@ static ssize_t reipl_generic_loadparm_store(struct ipl_parameter_block *ipb,
 	/* copy and convert to ebcdic */
 	memcpy(ipb->hdr.loadparm, buf, lp_len);
 	ASCEBC(ipb->hdr.loadparm, LOADPARM_LEN);
+	ipb->hdr.flags |= DIAG308_FLAGS_LP_VALID;
 	return len;
 }