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/pci_tegra.c b/drivers/pci/pci_tegra.c
index fc05ee0..f8d66c0 100644
--- a/drivers/pci/pci_tegra.c
+++ b/drivers/pci/pci_tegra.c
@@ -325,8 +325,8 @@
 	/* fixup root port class */
 	if (PCI_BUS(bdf) == 0) {
 		if ((offset & ~3) == PCI_CLASS_REVISION) {
-			value &= ~0x00ff0000;
-			value |= PCI_CLASS_BRIDGE_PCI << 16;
+			value &= ~0x00ffff00;
+			value |= PCI_CLASS_BRIDGE_PCI_NORMAL << 8;
 		}
 	}
 #endif