BACKPORT: scsi: ufs: Introduce ufs_hba_variant_params to group customizable parameters

The UFS driver is growing more and more customizable parameters. Collect
them in one place.

Link: https://lore.kernel.org/r/20200509093716.21010-2-stanley.chu@mediatek.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>

Bug: 151050916
(cherry picked from commit 90b8491c0033915ec1b290bc1c0de27935cb132d)
[ Resolved minor conflict in drivers/scsi/ufs/ufshcd.h ]
Change-Id: I6bddf3e39b38714db0053c606e75dd4d6fb4d0be
Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>