Bluetooth: Fix warning: using int as NULL pointer

Fix for warnings below:

...
drivers/bluetooth/bt3c_cs.c:667:20: warning: Using plain integer
	as NULL pointer
drivers/bluetooth/btuart_cs.c:596:20: warning: Using plain integer
	as NULL pointer
...

Signed-off-by: Andrei Emeltchenko <andrei.emeltchenko@intel.com>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
diff --git a/drivers/bluetooth/bt3c_cs.c b/drivers/bluetooth/bt3c_cs.c
index b2b0fbb..8925b6d 100644
--- a/drivers/bluetooth/bt3c_cs.c
+++ b/drivers/bluetooth/bt3c_cs.c
@@ -664,7 +664,7 @@
 {
 	int *try = priv_data;
 
-	if (try == 0)
+	if (!try)
 		p_dev->io_lines = 16;
 
 	if ((p_dev->resource[0]->end != 8) || (p_dev->resource[0]->start == 0))