Staging: hv: Move the definition of stor_vsc_initialize()

Since stor_vsc_initialize() is only used in storvs_drv.c, move this
function to storvsc_drv.c.

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>