scsi: ufs: core: Export ufshcd_schedule_eh_work()

Make it possible to call ufshcd_schedule_eh_work() from other source files
than ufshcd.c. Additionally, convert a source code comment into a
lockdep_assert_held() call.

Link: https://lore.kernel.org/r/20211020214024.2007615-6-bvanassche@acm.org


Acked-by: Avri Altman <Avri.Altman@wdc.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>