UPSTREAM: loop: unset GENHD_FL_NO_PART_SCAN on LOOP_CONFIGURE

When LOOP_CONFIGURE is used with LO_FLAGS_PARTSCAN we need to propagate
this into the GENHD_FL_NO_PART_SCAN. LOOP_SETSTATUS does this,
LOOP_CONFIGURE doesn't so far. Effect is that setting up a loopback
device with partition scanning doesn't actually work when LOOP_CONFIGURE
is issued, though it works fine with LOOP_SETSTATUS.

Let's correct that and propagate the flag in LOOP_CONFIGURE too.

Fixes: 3448914e8cc5("loop: Add LOOP_CONFIGURE ioctl")

Signed-off-by: Lennart Poettering <lennart@poettering.net>
Acked-by: Martijn Coenen <maco@android.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
(cherry picked from commit fe6a8fc5ed2f0081f17375ae2005718522c392c6)
Bug: 187129171
Signed-off-by: Connor O'Brien <connoro@google.com>
Change-Id: I0f541040a6bff3d682108bea213b57f89a531272