scsi: ufs: allow custom delay prior to host enabling

Currently a 1 ms delay is applied before polling CONTROLLER_ENABLE
bit. This delay may not be required or can be changed in different
controllers. Make the delay as a changeable value in struct ufs_hba to
allow it customized by vendors.

Link: https://lore.kernel.org/r/20200318104016.28049-6-stanley.chu@mediatek.com


Reviewed-by: Avri Altman <avri.altman@wdc.com>
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>