remove GENHD_FL_UP

Hi Jens,

this series first cleans up various drivers to not rely on the
internal GENHD_FL_UP to decided if they need to call del_gendisk
and then removes the flag entirely.

Diffstat:
 block/genhd.c                 |    6 -
 block/partitions/core.c       |    4 -
 drivers/block/sx8.c           |    2 
 drivers/md/bcache/super.c     |   26 ++++---
 drivers/md/md.h               |    4 -
 drivers/mmc/core/block.c      |  143 +++++++++++++++++-------------------------
 drivers/nvme/host/core.c      |   16 ++--
 drivers/nvme/host/multipath.c |    2 
 fs/block_dev.c                |    2 
 include/linux/genhd.h         |    9 +-
 10 files changed, 93 insertions(+), 121 deletions(-)