dt-bindings: PCI: ti,am65: Extend for use with PVU

dt-bindings: PCI: ti,am65: Extend for use with PVU

The Peripheral Virtualization Unit (PVU) on the AM65 SoC is capable of
restricting DMA from PCIe devices to specific regions of host memory.
Add the optional property "memory-regions" to point to such regions of
memory when PVU is used.

Since the PVU deals with system physical addresses, utilizing the PVU
with PCIe devices also requires setting up the VMAP registers to map the
Requester ID of the PCIe device to the CBA Virtual ID, which in turn is
mapped to the system physical address. Hence, describe the VMAP
registers which are optional unless the PVU shall be used for PCIe.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Li Hua Qian <huaqian.li@siemens.com>
[mani: Expanded PVU in description]
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://patch.msgid.link/20250728023701.116963-3-huaqian.li@siemens.com