Staging: hv: storvsc: Cleanup the module init function in storvsc_drv.c

Get rid of unnecessary layering in the module init path.

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