USB: fix create_pipe()

create_pipe() can give wrong result if an expression is passed as the 'endpoint'
argument -- due to missing parentheses.

Thanks to Martin Mueller for finding the bug and providing the patch.
Signed-off-by: NSergei Shtylyov <sshtylyov@ru.mvista.com>

include/usb.h

@@ -259,7 +259,7 @@ int usb_set_interface(struct usb_device *dev, int interface, int alternate);
  */
 /* Create various pipes... */
 #define create_pipe(dev,endpoint) \
-		(((dev)->devnum << 8) | (endpoint << 15) | \
+		(((dev)->devnum << 8) | ((endpoint) << 15) | \
 		((dev)->speed << 26) | (dev)->maxpacketsize)
 #define default_pipe(dev) ((dev)->speed << 26)