ath5k: avoid PCI FATAL interrupts by restoring RETRY_TIMEOUT disabling

This reverts 'ath5k: remove dummy PCI "retry timeout" fix' on the
same theory as in 'ath9k: Fix PCI FATAL interrupts by restoring
RETRY_TIMEOUT disabling'.
Reported-by: NBob Copeland <me@bobcopeland.com>
Cc: stable@kernel.org
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath5k/base.c

@@ -686,6 +686,13 @@ ath5k_pci_resume(struct pci_dev *pdev)
 	if (err)
 		return err;
 
+	/*
+	 * Suspend/Resume resets the PCI configuration space, so we have to
+	 * re-disable the RETRY_TIMEOUT register (0x41) to keep
+	 * PCI Tx retries from interfering with C3 CPU state
+	 */
+	pci_write_config_byte(pdev, 0x41, 0);
+
 	err = request_irq(pdev->irq, ath5k_intr, IRQF_SHARED, "ath", sc);
 	if (err) {
 		ATH5K_ERR(sc, "request_irq failed\n");