Staging: hv: create VMBUS_DEVICE macro and use it.

This is to be used to be able to write hv_vmbus_device_id tables easier.

This patch also converts all hv drivers to use the macro, saving some
lines of code and making things easier to read overall.

Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>