pci: Add defines for normal and subtractive PCI bridges

Add following two new PCI class codes defines into pci_ids.h include file:

  PCI_CLASS_BRIDGE_PCI_NORMAL
  PCI_CLASS_BRIDGE_PCI_SUBTRACTIVE

And use these defines in all U-Boot code for describing PCI class codes for
normal and subtractive PCI bridges.

Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/drivers/pci/pcie_iproc.c b/drivers/pci/pcie_iproc.c
index 85dfab5..d6d3a9e 100644
--- a/drivers/pci/pcie_iproc.c
+++ b/drivers/pci/pcie_iproc.c
@@ -1123,7 +1123,7 @@
 				    PCI_BRIDGE_CTRL_REG_OFFSET,
 				    4, &class);
 	class &= ~PCI_BRIDGE_CTRL_REG_CLASS_MASK;
-	class |= (PCI_CLASS_BRIDGE_PCI << 8);
+	class |= PCI_CLASS_BRIDGE_PCI_NORMAL;
 	iproc_pci_raw_config_write32(pcie, 0,
 				     PCI_BRIDGE_CTRL_REG_OFFSET,
 				     4, class);