staging: unisys: visorchannel.c remove unneeded parenthesis

Fix the checkpatch.pl -strict check:

CHECK: Unnecessary parentheses around sig_hdr.num_overflows
+                                  &(sig_hdr.num_overflows),
Signed-off-by: David Kershner <david.kershner@unisys.com>
Signed-off-by: Benjamin Romer <benjamin.romer@unisys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/unisys/visorbus/visorchannel.c

@@ -468,7 +468,7 @@ signalinsert_inner(struct visorchannel *channel, u32 queue, void *msg)
 				   SIG_QUEUE_OFFSET(&channel->chan_hdr, queue) +
 				   offsetof(struct signal_queue_header,
 					    num_overflows),
-				   &(sig_hdr.num_overflows),
+				   &sig_hdr.num_overflows,
 				   sizeof(sig_hdr.num_overflows));
 		return false;
 	}