scsi: ufs: Move UFS trace events to private header

scsi: ufs: Move UFS trace events to private header

UFS trace events are called exclusively from the UFS core drivers.  Make
those events private to the core driver.

The MAINTAINERS file does not need updating as the maintainership remains
the same and the relevant directory is already covered.

Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Avri Altman <avri.altman@wdc.com>
Link: https://lore.kernel.org/r/20240821055411.3128159-1-avri.altman@wdc.com
Acked-by: Bean Huo <beanhuo@micron.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>