mwifiex: remove MWIFIEX_BSS_MODE_ macros

replace them with NL80211_IFTYPE_ macros

Also remove redundant functions mwifiex_drv_get_mode()
and mwifiex_bss_ioctl_mode().

Signed-off-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/mwifiex/sta_event.c b/drivers/net/wireless/mwifiex/sta_event.c
index d4a5c1f..0187185 100644
--- a/drivers/net/wireless/mwifiex/sta_event.c
+++ b/drivers/net/wireless/mwifiex/sta_event.c
@@ -82,7 +82,7 @@
 	priv->is_data_rate_auto = true;
 	priv->data_rate = 0;
 
-	if (priv->bss_mode == MWIFIEX_BSS_MODE_IBSS) {
+	if (priv->bss_mode == NL80211_IFTYPE_ADHOC) {
 		priv->adhoc_state = ADHOC_IDLE;
 		priv->adhoc_is_link_sensed = false;
 	}