block: Remove blk_set_runtime_active()

The function blk_set_runtime_active() is called only from
blk_post_runtime_resume(), so there is no need for that function to be
exported. Open-code this function directly in blk_post_runtime_resume()
and remove it.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20231120070611.33951-1-dlemoal@kernel.org


Signed-off-by: Jens Axboe <axboe@kernel.dk>