staging: lustre: ptlrpc: silence a shift wrapping warning

"svcpt->scp_hist_seq" is a u64 so static checkers complain that 1U
should be 1ULL.  I looked at REQS_SEQ_SHIFT() a little and it seems to
be capped by the number of CPUs online and the amount of memory, but I
think it could go above 32 possibly.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/ptlrpc/events.c

@@ -277,7 +277,7 @@ static void ptlrpc_req_add_history(struct ptlrpc_service_part *svcpt,
 		 * then we hope there will be less RPCs per bucket at some
 		 * point, and sequence will catch up again
 		 */
-		svcpt->scp_hist_seq += (1U << REQS_SEQ_SHIFT(svcpt));
+		svcpt->scp_hist_seq += (1ULL << REQS_SEQ_SHIFT(svcpt));
 		new_seq = svcpt->scp_hist_seq;
 	}