[S390] provide documentation for hvc_iucv kernel parameter.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 09ede6c..12f0fb6 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -814,6 +814,9 @@
 
 	hlt		[BUGS=ARM,SH]
 
+	hvc_iucv=	[S390] Number of z/VM IUCV Hypervisor console (HVC)
+			       back-ends. Valid parameters: 0..8
+
 	i8042.debug	[HW] Toggle i8042 debug mode
 	i8042.direct	[HW] Put keyboard port into non-translated mode
 	i8042.dumbkbd	[HW] Pretend that controller can only read data from