staging: wilc1000: fix NULL comparison style

This patch fixes NULL comparison style found by checkpatch.pl.

CHECK: Comparison to NULL could be written "!net"
CHECK: Comparison to NULL could be written "!net->ieee80211_ptr"
CHECK: Comparison to NULL could be written "!net->ieee80211_ptr->wiphy"

Signed-off-by: Chaehyun Lim <chaehyun.lim@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/staging/wilc1000/wilc_wfi_cfgoperations.c b/drivers/staging/wilc1000/wilc_wfi_cfgoperations.c
index e51745e..af11af3 100644
--- a/drivers/staging/wilc1000/wilc_wfi_cfgoperations.c
+++ b/drivers/staging/wilc1000/wilc_wfi_cfgoperations.c
@@ -3694,17 +3694,17 @@
 
 	PRINT_D(CFG80211_DBG, "Unregistering wiphy\n");
 
-	if (net == NULL) {
+	if (!net) {
 		PRINT_D(INIT_DBG, "net_device is NULL\n");
 		return;
 	}
 
-	if (net->ieee80211_ptr == NULL) {
+	if (!net->ieee80211_ptr) {
 		PRINT_D(INIT_DBG, "ieee80211_ptr is NULL\n");
 		return;
 	}
 
-	if (net->ieee80211_ptr->wiphy == NULL) {
+	if (!net->ieee80211_ptr->wiphy) {
 		PRINT_D(INIT_DBG, "wiphy is NULL\n");
 		return;
 	}