mmc: sdhi: Convert from tasklet to BH workqueue

The only generic interface to execute asynchronously in the BH context is
tasklet; however, it's marked deprecated and has some design flaws. To
replace tasklets, BH workqueue support was recently added. A BH workqueue
behaves similarly to regular workqueues except that the queued work items
are executed in the BH context.

This patch converts the SDHI driver from tasklet to BH workqueue.

Based on the work done by Tejun Heo <tj@kernel.org>

Signed-off-by: Allen Pais <allen.lkml@gmail.com>
[wsa: fixed build faliures, corrected whitespace issues]
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20240626085015.32171-2-wsa+renesas@sang-engineering.com


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>