Currently driver ktime stats, measuring code paths, is NVME-specific.

Convert the stats routines such that the code paths are generic, providing
status for NVME and SCSI. Added ktime stat calls in SCSI queuecommand and
cmpl routines.

Link: https://lore.kernel.org/r/20200322181304.37655-11-jsmart2021@gmail.comSigned-off-by: NJames Smart <jsmart2021@gmail.com>
Signed-off-by: NDick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>