drivers/*: mark variables with uninitialized_var()

Mark variables in drivers/* with uninitialized_var() if such a warning
appears, and analysis proves that the var is initialized properly on all
paths it is used.

Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/net/r8169.c b/drivers/net/r8169.c
index 982a901..bb6896a 100644
--- a/drivers/net/r8169.c
+++ b/drivers/net/r8169.c
@@ -2338,7 +2338,7 @@
 {
 	struct skb_shared_info *info = skb_shinfo(skb);
 	unsigned int cur_frag, entry;
-	struct TxDesc *txd;
+	struct TxDesc * uninitialized_var(txd);
 
 	entry = tp->cur_tx;
 	for (cur_frag = 0; cur_frag < info->nr_frags; cur_frag++) {