ublk: don't clear GD_SUPPRESS_PART_SCAN for unprivileged daemons

ublk: don't clear GD_SUPPRESS_PART_SCAN for unprivileged daemons

When UBLK_F_NO_AUTO_PART_SCAN is set, GD_SUPPRESS_PART_SCAN is cleared
unconditionally, including for unprivileged daemons. Keep it consistent
with the code block for setting GD_SUPPRESS_PART_SCAN by not clearing
it for unprivileged daemons.

In reality this isn't a problem because ioctl(BLKRRPART) requires
CAP_SYS_ADMIN, but it is more reliable to not clear the bit.

Cc: Alexander Atanasov <alex@zazolabs.com>
Fixes: 8443e2087e70 ("ublk: add UBLK_F_NO_AUTO_PART_SCAN feature flag")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>