dt-bindings: PCI: Document "atu" reg-names

Document "atu" reg-names required to get the register space for ATU in
Synopsys designware core version >= 4.80.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
This commit is contained in:
Kishon Vijay Abraham I 2019-03-25 15:09:30 +05:30 • committed by Lorenzo Pieralisi
commit 26f51e85b3