We already have a queue for the requested memory ranges which contains
'lp_req' objects. These objects hold the same information as the lazy_iov:
start address of the range, end address and the address that the range had
at the dump time.

Rather than keep this information twice and use double bookkeeping, we can
extract the requested range from lpi->iovs and move it to lpi->reqs.
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>