Staging: hv: util: Get rid of the PCI signature in hv_util.c

Now that we have implemented a vmbus specific mechanism for auto-loading,
get rid of the PCI signature.

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