Staging: hv: Move the contents of blkvsc.c to blkvsc_drv.c

In preparation for getting rid of the file blkvsc.c, move its contents
to the appropriate file.

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