clean up bvec iter helpers

[Christoph Hellwig]

Hi all,

this series converts the bvec_iter helpers from macros to inline
functions, and to facilitate that cleans up a little bit of code
in the loop and nvme-tcp drivers first.

Diffstat:
 drivers/block/loop.c    |   24 ++++-------
 drivers/nvme/host/tcp.c |   27 ++++--------
 include/linux/bvec.h    |  101 ++++++++++++++++++++++++++++++------------------
 3 files changed, 84 insertions(+), 68 deletions(-)