PCI: j721e: Make TI J721E depend on ARCH_K3

The J721E PCIe is hardware specific to TI SoC parts so add a dependency
on that so it's available for those SoC parts and for compile testing but
not necessarily everyone who enables the Cadence PCIe controller.

Link: https://lore.kernel.org/linux-pci/20240104213910.1426843-1-pbrobinson@gmail.com
Signed-off-by: Peter Robinson <pbrobinson@gmail.com>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>

PCI: Use consistent controller Kconfig menu entry language

Use "PCIe controller" consistently instead of "host bridge", "bus driver",
etc. Annotate with "(host mode)" or "(endpoint mode)" as needed.

Link: https://lore.kernel.org/r/20230418174336.145585-5-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

PCI: j721e: Add TI J721E PCIe driver

Add support for PCIe controller in J721E SoC. The controller uses the
Cadence PCIe core programmed by pcie-cadence*.c. The PCIe controller
will work in both host mode and device mode.
Some of the features of the controller are:
*) Supports both RC mode and EP mode
*) Supports MSI and MSI-X support
*) Supports upto GEN3 speed mode
*) Supports SR-IOV capability
*) Ability to route all transactions via SMMU (support will be added
in a later patch).

Link: https://lore.kernel.org/r/20200722110317.4744-14-kishon@ti.com
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

PCI: cadence: Move all files to per-device cadence directory

Cadence core library files may be used by various platform drivers.
Add a new directory "cadence" to group all the Cadence core library files
and the platforms using Cadence core library.

Signed-off-by: Tom Joseph <tjoseph@cadence.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Andrew Murray <andrew.murray@arm.com>