RDMA/siw: Fix a memory leak in siw_init_cpulist()

The error handling code doesn't free siw_cpu_info.tx_valid_cpus[0].  The
first iteration through the loop is a no-op so this is sort of an off
by one bug.  Also Bernard pointed out that we can remove the NULL
assignment and simplify the code a bit.

Fixes: bdcf26bf9b ("rdma/siw: network and RDMA core interface")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Bernard Metzler <bmt@zurich.ibm.com>
Reviewed-by: Bernard Metzler <bmt@zurich.ibm.com>
Link: https://lore.kernel.org/r/20190809140904.GB3552@mwanda
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/sw/siw/siw_main.c

@@ -160,10 +160,8 @@ static int siw_init_cpulist(void)
 
 out_err:
 	siw_cpu_info.num_nodes = 0;
-	while (i) {
+	while (--i >= 0)
 		kfree(siw_cpu_info.tx_valid_cpus[i]);
-		siw_cpu_info.tx_valid_cpus[i--] = NULL;
-	}
 	kfree(siw_cpu_info.tx_valid_cpus);
 	siw_cpu_info.tx_valid_cpus = NULL;