scsi: ufs: use an enum for host capabilities

scsi: ufs: use an enum for host capabilities

Use an enum to specify the host capabilities instead of #defines inside the
structure definition.

Link: https://lore.kernel.org/r/20200318104016.28049-3-stanley.chu@mediatek.com
Reviewed-by: Avri Altman <avri.altman@wdc.com>
Reviewed-by: Can Guo <cang@codeaurora.org>
Reviewed-by: Bean Huo <beanhuo@micron.com>
Reviewed-by: Asutosh Das <asutoshd@codeaurora.org>
Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>