FROMLIST: scsi: ufs: Allow async suspend/resume callbacks

Allow UFS suspend/resume callbacks to run in parallel with other
suspend/resume callbacks. This can recoup dozens of milliseconds on the
resume path if UFS hardware needs to be powered back on.

Suspending and resuming asynchronously is safe to do so long as the driver
callbacks only depend on resources made available by either a) parent
devices or b) devices explicitly marked as suppliers with device_link_add.

Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Bart Van Assche <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>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Vincent Palomares <paillon@google.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Vincent Palomares <paillon@google.com>
Link: https://lore.kernel.org/linux-scsi/a7091f96-12a3-a244-040a-c41a7c5e3617@acm.org/T/#t
Bug: 194213025
Change-Id: I46ff584d3a1342ab3b26ffdf196e7a65637294f3