PCI: keystone: Fix outbound region mapping

The Keystone outbound Address Translation Unit (ATU) maps PCI MMIO space in
8 MB windows.  When programming the ATU windows, we previously incremented
the starting address by 8, not 8 MB, so all the windows were mapped to the
first 8 MB.  Therefore, only 8 MB of MMIO space was accessible.

Update the loop so it increments the starting address by 8 MB, not 8, so
more MMIO space is accessible.

Fixes: e75043ad ("PCI: keystone: Cleanup outbound window configuration")
Link: https://lore.kernel.org/r/20191004154811.GA31397@monakov-y.office.kontur-niirs.ru


Signed-off-by: Yurii Monakov <monakov.y@gmail.com>
[bhelgaas: commit log]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Andrew Murray <andrew.murray@arm.com>
Acked-by: Kishon Vijay Abraham I <kishon@ti.com>
Cc: stable@vger.kernel.org	# v4.20+