[patch] mailbox: bcm-pdc: potential NULL dereference in pdc_shutdown()

[Dan Carpenter]

We can't pass NULL pointers to pdc_ring_free() so I moved the check for
NULL.

Signed-off-by: Dan Carpenter <dan.carpen...@oracle.com>

diff --git a/drivers/mailbox/bcm-pdc-mailbox.c 
b/drivers/mailbox/bcm-pdc-mailbox.c
index cbe0c1e..c56d4d0 100644
--- a/drivers/mailbox/bcm-pdc-mailbox.c
+++ b/drivers/mailbox/bcm-pdc-mailbox.c
@@ -1191,10 +1191,11 @@ static void pdc_shutdown(struct mbox_chan *chan)
 {
        struct pdc_state *pdcs = chan->con_priv;
 
-       if (pdcs)
-               dev_dbg(&pdcs->pdev->dev,
-                       "Shutdown mailbox channel for PDC %u", pdcs->pdc_idx);
+       if (!pdcs)
+               return;
 
+       dev_dbg(&pdcs->pdev->dev,
+               "Shutdown mailbox channel for PDC %u", pdcs->pdc_idx);
        pdc_ring_free(pdcs);
 }