staging: hv: use delayed_work for netvsc_send_garp()

Instead of sleeping in a scheduled work, we now use delayed_work
for netvsc_send_garp().

Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Hank Janssen <hjanssen@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Cc: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>