Staging: hv: coding style cleanups for netvsc_drv.c

There are still some horrible long lines in here, which some simple
code reworking will make smaller and easier to understand.

Also note the FIXME in struct netvsc_driver_context...

Cc: Hank Janssen <hjanssen@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>