[S390] incorrect reipl nss name.

/sys/firmware/reipl/nss/name contains the nss name when defsys or
savesys command has been executed. If the defsys or savesys command
fails the kernel_nss_name has to be cleared since a reipl on that
nss name won't be possible.

Signed-off-by: Hongjie Yang <[e-mail]>
Signed-off-by: Martin Schwidefsky <[e-mail]>

arch/s390/kernel/early.c

···
 
 	__cpcmd(defsys_cmd, NULL, 0, &response);
 
-	if (response != 0)
+	if (response != 0) {
+		kernel_nss_name[0] = '\0';
 		return;
+	}
 
 	__cpcmd(savesys_cmd, NULL, 0, &response);
 
-	if (response != strlen(savesys_cmd))
+	if (response != strlen(savesys_cmd)) {
+		kernel_nss_name[0] = '\0';
 		return;
+	}
 
 	ipl_flags = IPL_NSS_VALID;
 }