staging: et131x: Use pci_dev->pcie_mpss and pcie_set_readrq() to simplify code

The PCI core caches the "PCIe Max Payload Size Supported" in
pci_dev->pcie_mpss, so use that instead of pcie_capability_read_dword().
Also use pcie_set_readrq() instead of pcie_capability_clear_and_set_word()
to simplify code.
Signed-off-by: NYijing Wang <wangyijing@huawei.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: NMark Einon <mark.einon@gmail.com>

drivers/staging/et131x/et131x.c

@@ -3605,17 +3605,10 @@ static int et131x_pci_init(struct et131x_adapter *adapter,
 		goto err_out;
 	}
 
-	/* Let's set up the PORT LOGIC Register.  First we need to know what
-	 * the max_payload_size is
-	 */
-	if (pcie_capability_read_word(pdev, PCI_EXP_DEVCAP, &max_payload)) {
-		dev_err(&pdev->dev,
-		    "Could not read PCI config space for Max Payload Size\n");
-		goto err_out;
-	}
+	/* Let's set up the PORT LOGIC Register. */
 
 	/* Program the Ack/Nak latency and replay timers */
-	max_payload &= 0x07;
+	max_payload = pdev->pcie_mpss;
 
 	if (max_payload < 2) {
 		static const u16 acknak[2] = { 0x76, 0xD0 };
@@ -3645,8 +3638,7 @@ static int et131x_pci_init(struct et131x_adapter *adapter,
 	}
 
 	/* Change the max read size to 2k */
-	if (pcie_capability_clear_and_set_word(pdev, PCI_EXP_DEVCTL,
-				PCI_EXP_DEVCTL_READRQ, 0x4 << 12)) {
+	if (pcie_set_readrq(pdev, 2048)) {
 		dev_err(&pdev->dev,
 			"Couldn't change PCI config space for Max read size\n");
 		goto err_out;