FROMLIST: ufs: introduce a callback to get info of command completion

Some SoC specific might need command history for
various reasons, such as stacking command contexts
in system memory to check for debugging in the future
or scaling some DVFS knobs to boost IO throughput.

What you would do with the information could be
variant per SoC vendor.

Bug: 163100341
Link: https://lore.kernel.org/linux-scsi/159530290480.22526.15318134249960762889.b4-ty@oracle.com/T/#t


Change-Id: I39a30ff742d3a2eebb66decb651e4cf5b990c1eb
Signed-off-by: Kiwoong Kim <kwmad.kim@samsung.com>
Acked-by: Stanley Chu <stanley.chu@mediatek.com>
Reviewed-by: Avri Altman <avri.altman@wdc.com>