9p: Fix sparse error

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
diff --git a/net/9p/protocol.c b/net/9p/protocol.c
index 8a4084f..a7e8997 100644
--- a/net/9p/protocol.c
+++ b/net/9p/protocol.c
@@ -468,7 +468,8 @@
 		case 'E':{
 				 int32_t cnt = va_arg(ap, int32_t);
 				 const char *k = va_arg(ap, const void *);
-				 const char *u = va_arg(ap, const void *);
+				 const char __user *u = va_arg(ap,
+							const void __user *);
 				 errcode = p9pdu_writef(pdu, proto_version, "d",
 						 cnt);
 				 if (!errcode && pdu_write_urw(pdu, k, u, cnt))