Staging: hv: Get rid of the type field from struct hv_storvsc_request

In preparation for consolidating all I/O request state, get rid of the
type field from struct hv_storvsc_request and instead use the
equivalent  state in struct vmscsi_request - data_in field.
In the current code there is a call to zero out the struct vstor_packet in
stor_vsc_on_io_request(). So, to be able to directly set the state in the
vstor_packet in blkvsc_drv.c and storvsc_drv.c, get rid of the call to
zero out the packet in stor_vsc_on_io_request() and instead allocate the
request structure that has been zeroed out.

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: Hank Janssen <hjanssen@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>