mwifiex: remove global variable cmd_wait_q_required

There is a race condition while queuing synchronous command and
asynchronous command requested from different threads, because
the wait_q_enabled flag is set based on a global variable
cmd_wait_q_required.

The issue is fixed by removing this global variable and using a
unified function with an argument 'sync' passed into the
function.

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/util.c b/drivers/net/wireless/mwifiex/util.c
index 8d37bfc..098de88 100644
--- a/drivers/net/wireless/mwifiex/util.c
+++ b/drivers/net/wireless/mwifiex/util.c
@@ -72,7 +72,7 @@
 		return -1;
 	}
 
-	return mwifiex_send_cmd_sync(priv, cmd, HostCmd_ACT_GEN_SET, 0, NULL);
+	return mwifiex_send_cmd(priv, cmd, HostCmd_ACT_GEN_SET, 0, NULL, true);
 }
 EXPORT_SYMBOL_GPL(mwifiex_init_shutdown_fw);