FROMLIST: scsi: ufs: Fix deadlocks between power management and error handler

The following deadlocks have been observed on multiple test setups:

* ufshcd_wl_suspend() is waiting for blk_execute_rq() to complete while it
  holds host_sem.
* ufshcd_eh_host_reset_handler() invokes ufshcd_err_handler() and the
  latter function tries to obtain host_sem.
This is a deadlock because blk_execute_rq() can't execute SCSI commands
while the host is in the SHOST_RECOVERY state and because the error
handler cannot make progress either.

* ufshcd_wl_runtime_resume() is waiting for blk_execute_rq() to finish
  while it holds host_sem.
* ufshcd_eh_host_reset_handler() invokes ufshcd_err_handler() and the
  latter function calls pm_runtime_resume().
This is a deadlock because of the same reason as the previous scenario.

Fix both deadlocks by not obtaining host_sem from the power management
code paths. Removing the host_sem locking from the power management code
is safe because the ufshcd_err_handler() is already serialized against
SCSI command execution.

Cc: dh0421.hwang@samsung.com
Cc: Asutosh Das <asutoshd@codeaurora.org>
Fixes: b294ff3e ("scsi: ufs: core: Enable power management for wlun")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Bug: 240498410
Bug: 246990788
Bug: 247073231
Bug: 247081382
Bug: 247082093
Link: https://lore.kernel.org/linux-scsi/


Signed-off-by: Bart Van Assche <bvanassche@google.com>
Change-Id: Ifb9b429ba89ff6d8a133d96a172eaefc09d85955