PCI: Export pcie_set_mps() and pcie_get_mps()

Export pcie_get_mps() and pcie_set_mps() functions so drivers can use
them to simplify code.

Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index e8ccf6c..8c81246 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -3972,6 +3972,7 @@
 
 	return 128 << ((ctl & PCI_EXP_DEVCTL_PAYLOAD) >> 5);
 }
+EXPORT_SYMBOL(pcie_get_mps);
 
 /**
  * pcie_set_mps - set PCI Express maximum payload size
@@ -3996,6 +3997,7 @@
 	return pcie_capability_clear_and_set_word(dev, PCI_EXP_DEVCTL,
 						  PCI_EXP_DEVCTL_PAYLOAD, v);
 }
+EXPORT_SYMBOL(pcie_set_mps);
 
 /**
  * pcie_get_minimum_link - determine minimum link settings of a PCI device