The firmware is cached during the first successfull call to open() and
released once the network device is unregistered. The driver uses the
cached firmware between open() and unregister_netdev().

So far the firmware is optional : a failure to load the firmware does
not prevent open() to success. It is thus necessary to 1) unregister
all 816x / 810[23] devices and 2) force a driver probe to issue a new
firmware load.
Signed-off-by: NFrancois Romieu <romieu@fr.zoreil.com>
Fixed-by: NCiprian Docan <docan@eden.rutgers.edu>
Cc: Realtek linux nic maintainers <nic_swsd@realtek.com>