b43: Remove irqs_disabled() sanity checks

Remove all irqs_disabled() sanity checks, as they are not safe on
a RT-enabled kernel and will trigger bogus warnings.

Signed-off-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/b43/dma.c b/drivers/net/wireless/b43/dma.c
index 766d955..cfbc1a2 100644
--- a/drivers/net/wireless/b43/dma.c
+++ b/drivers/net/wireless/b43/dma.c
@@ -1344,6 +1344,7 @@
 	return err;
 }
 
+/* Called with IRQs disabled. */
 void b43_dma_handle_txstatus(struct b43_wldev *dev,
 			     const struct b43_txstatus *status)
 {
@@ -1356,8 +1357,8 @@
 	ring = parse_cookie(dev, status->cookie, &slot);
 	if (unlikely(!ring))
 		return;
-	B43_WARN_ON(!irqs_disabled());
-	spin_lock(&ring->lock);
+
+	spin_lock(&ring->lock); /* IRQs are already disabled. */
 
 	B43_WARN_ON(!ring->tx);
 	ops = ring->ops;