spi/dw_spi: add a missed dw_spi_remove_host() in exit sequence

Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/drivers/spi/dw_spi_pci.c b/drivers/spi/dw_spi_pci.c
index 34ba691..7980f14 100644
--- a/drivers/spi/dw_spi_pci.c
+++ b/drivers/spi/dw_spi_pci.c
@@ -98,6 +98,7 @@
 	struct dw_spi_pci *dwpci = pci_get_drvdata(pdev);
 
 	pci_set_drvdata(pdev, NULL);
+	dw_spi_remove_host(&dwpci->dws);
 	iounmap(dwpci->dws.regs);
 	pci_release_region(pdev, 0);
 	kfree(dwpci);