scsi: ufs: Use DECLARE_COMPLETION_ONSTACK() where appropriate

From Documentation/scheduler/completion.rst: "When a completion is declared
as a local variable within a function, then the initialization should
always use DECLARE_COMPLETION_ONSTACK() explicitly, not just to make
lockdep happy, but also to make it clear that limited scope had been
considered and is intentional."

Link: https://lore.kernel.org/r/20210722033439.26550-6-bvanassche@acm.org


Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Stanley Chu <stanley.chu@mediatek.com>
Cc: Can Guo <cang@codeaurora.org>
Cc: Asutosh Das <asutoshd@codeaurora.org>
Cc: Avri Altman <avri.altman@wdc.com>
Reviewed-by: Avri Altman <avri.altman@wdc.com>
Reviewed-by: Bean Huo <beanhuo@micron.com>
Reviewed-by: Daejun Park <daejun7.park@samsung.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>