mwifiex: fix 'Smatch' warnings

Following three warnings are fixed:

>init.c +256 mwifiex_init_adapter(71)
>warn: variable dereferenced before check 'adapter->sleep_cfm'
>(see line 191)

>sta_rx.c +193 mwifiex_process_sta_rx_packet(75)
>warn: variable dereferenced before check 'priv' (see line 182)

Signed-off-by: Yogesh Ashok Powar <yogeshp@marvell.com>
Signed-off-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/mwifiex/sta_rx.c b/drivers/net/wireless/mwifiex/sta_rx.c
index 2743051..5e1ef7e 100644
--- a/drivers/net/wireless/mwifiex/sta_rx.c
+++ b/drivers/net/wireless/mwifiex/sta_rx.c
@@ -126,6 +126,9 @@
 	u16 rx_pkt_type;
 	struct mwifiex_private *priv = adapter->priv[rx_info->bss_index];
 
+	if (!priv)
+		return -1;
+
 	local_rx_pd = (struct rxpd *) (skb->data);
 	rx_pkt_type = local_rx_pd->rx_pkt_type;
 
@@ -189,12 +192,11 @@
 					     (u8) local_rx_pd->rx_pkt_type,
 					     skb);
 
-	if (ret || (rx_pkt_type == PKT_TYPE_BAR)) {
-		if (priv && (ret == -1))
-			priv->stats.rx_dropped++;
-
+	if (ret || (rx_pkt_type == PKT_TYPE_BAR))
 		dev_kfree_skb_any(skb);
-	}
+
+	if (ret)
+		priv->stats.rx_dropped++;
 
 	return ret;
 }