iommu/mediatek: Fix iova_to_phys PA start for 4GB mode

iommu/mediatek: Fix iova_to_phys PA start for 4GB mode

In M4U 4GB mode, the physical address is remapped as below:

CPU Physical address:

====================

0      1G       2G     3G       4G     5G
|---A---|---B---|---C---|---D---|---E---|
+--I/O--+------------Memory-------------+

IOMMU output physical address:
 =============================

                                4G      5G     6G      7G      8G
                                |---E---|---B---|---C---|---D---|
                                +------------Memory-------------+

The Region 'A'(I/O) can not be mapped by M4U; For Region 'B'/'C'/'D', the
bit32 of the CPU physical address always is needed to set, and for Region
'E', the CPU physical address keep as is. something looks like this:
CPU PA         ->    M4U OUTPUT PA
0x4000_0000          0x1_4000_0000 (Add bit32)
0x8000_0000          0x1_8000_0000 ...
0xc000_0000          0x1_c000_0000 ...
0x1_0000_0000        0x1_0000_0000 (No change)

Additionally, the iommu consumers always use the CPU phyiscal address.

The PA in the iova_to_phys that is got from v7s always is u32, But
from the CPU point of view, PA only need add BIT(32) when PA < 0x4000_0000.

Fixes: 30e2fccf9512 ("iommu/mediatek: Enlarge the validate PA range
for 4GB mode")
Signed-off-by: Yong Wu <yong.wu@mediatek.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>