scsi: ufs: Refine error history functions

The UFS error history does not only have "history of errors" but also a
log of some other events which are not defined as errors.

This patch fixes the confused naming of related functions and changes the
approach for updating and printing history in preparation of next patch.

This patch does not change any functionality.

Link: https://lore.kernel.org/r/20201205115901.26815-3-stanley.chu@mediatek.com


Reviewed-by: Asutosh Das <asutoshd@codeaurora.org>
Reviewed-by: Can Guo <cang@codeaurora.org>
Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>