[usb] Add basic support for USB devices

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/include/ipxe/device.h

@@ -66,10 +66,13 @@ struct device_description {
 /** Hyper-V bus type */
 #define BUS_TYPE_HV 9
 
+/** USB bus type */
+#define BUS_TYPE_USB 10
+
 /** A hardware device */
 struct device {
 	/** Name */
-	char name[16];
+	char name[32];
 	/** Driver name */
 	const char *driver_name;
 	/** Device description */

src/include/ipxe/errfile.h

@@ -76,6 +76,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
 #define ERRFILE_pci		     ( ERRFILE_DRIVER | 0x00040000 )
 #define ERRFILE_linux		     ( ERRFILE_DRIVER | 0x00050000 )
 #define ERRFILE_pcivpd		     ( ERRFILE_DRIVER | 0x00060000 )
+#define ERRFILE_usb		     ( ERRFILE_DRIVER | 0x00070000 )
 
 #define ERRFILE_nvs		     ( ERRFILE_DRIVER | 0x00100000 )
 #define ERRFILE_spi		     ( ERRFILE_DRIVER | 0x00110000 )