scsi: storvsc: Retrieve information about the capability of the target

The storage protocol informs the guest of the I/O capabilities of the storage
stack. Retrieve this information and use it in the guest.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Long Li <longli@microsoft.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>