qed: Switch to .bdrv_co_block_status()

qed: Switch to .bdrv_co_block_status()

We are gradually moving away from sector-based interfaces, towards
byte-based.  Update the qed driver accordingly, taking the opportunity
to inline qed_is_allocated_cb() into its lone caller (the callback
used to be important, until we switched qed to coroutines).  There is
no intent to optimize based on the want_zero flag for this format.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>