Name
netdev_has_upper_dev — 
     Check if device is linked to an upper device
 
Arguments
- dev
- 
     device
     
- upper_dev
- 
     upper device to check
     
Description
   Find out if a device is linked to specified upper device and return true
   in case it is. Note that this checks only immediate upper device,
   not through a complete stack of devices. The caller must hold the RTNL lock.