Staging: hv: Replace typedef SG_BUFFER_LIST by struct scatterlist

typedef SG_BUFFER_LIST is removed and its uses are replaced by the use of
struct scatterlist.

Signed-off-by: Nicolas Palix <npalix@diku.dk>
Cc: Bill Pemberton <wfp5p@virginia.edu>
Cc: Hank Janssen <hjanssen@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>