iwlwifi: remove stray mutex_unlock()

This mutex_unlock() has been here from the initial commit, but as nearly
as I can tell, there isn't a reason for it.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwlwifi/iwl-3945.c

@@ -2482,7 +2482,6 @@ int iwl3945_hw_set_hw_params(struct iwl_priv *priv)
 				   &priv->_3945.shared_phys, GFP_KERNEL);
 	if (!priv->_3945.shared_virt) {
 		IWL_ERR(priv, "failed to allocate pci memory\n");
-		mutex_unlock(&priv->mutex);
 		return -ENOMEM;
 	}