ixgbe: Update ixgbe_disable_pcie_master flow for X550*

This patch skips the PCI transactions pending check in
ixgbe_disable_pcie_master. This is done to addresses a known HW
issue where the PCI transactions pending bit sticks high when there
are pending transactions. HW engineering instructed to workaround
this issue by wait and then continue with our reset flow.
Signed-off-by: Mark Rustad <mark.d.rustad@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/ixgbe/ixgbe_common.c

@@ -2476,6 +2476,9 @@ static s32 ixgbe_disable_pcie_master(struct ixgbe_hw *hw)
 	hw_dbg(hw, "GIO Master Disable bit didn't clear - requesting resets\n");
 	hw->mac.flags |= IXGBE_FLAGS_DOUBLE_RESET_REQUIRED;
 
+	if (hw->mac.type >= ixgbe_mac_X550)
+		return 0;
+
 	/*
 	 * Before proceeding, make sure that the PCIe block does not have
 	 * transactions pending.