PCI: Add Loongson vendor ID

Add the Loongson vendor ID to pci_ids.h to be used by the controller
driver in the future.

The Loongson vendor ID can be found at the following link:
https://git.kernel.org/pub/scm/utils/pciutils/pciutils.git/tree/pci.ids

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

include/linux/pci_ids.h

@@ -148,6 +148,8 @@
 
 /* Vendors and devices.  Sort key: vendor first, device next. */
 
+#define PCI_VENDOR_ID_LOONGSON		0x0014
+
 #define PCI_VENDOR_ID_TTTECH		0x0357
 #define PCI_DEVICE_ID_TTTECH_MC322	0x000a