etherdevice.h: fix kernel-doc typo

Fix etherdevice.h parameter name typo in kernel-doc:

Warning(include/linux/etherdevice.h:138): No description found for parameter 'hwaddr'
Warning(include/linux/etherdevice.h:138): Excess function parameter 'addr' description in 'dev_hw_addr_random'

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>