b43legacy: fix logic in GPIO init

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/b43legacy/main.c b/drivers/net/wireless/b43legacy/main.c
index 8156135..3ea1a85d 100644
--- a/drivers/net/wireless/b43legacy/main.c
+++ b/drivers/net/wireless/b43legacy/main.c
@@ -1920,7 +1920,7 @@
 		return 0;
 	ssb_write32(gpiodev, B43legacy_GPIO_CONTROL,
 		    (ssb_read32(gpiodev, B43legacy_GPIO_CONTROL)
-		     & mask) | set);
+		     & ~mask) | set);
 
 	return 0;
 }