PCI: rcar-gen4: Add support for R-Car V4H

PCI: rcar-gen4: Add support for R-Car V4H

Add support for r8a779g0 (R-Car V4H).

This driver previously supported r8a779f0 (R-Car S4-8). PCIe features
of both r8a779f0 and r8a779g0 are almost all the same. For example:

 - PCI Express Base Specification Revision 4.0
 - Root complex mode and endpoint mode are supported

However, r8a779g0 requires specific firmware to be provided, to
initialize the PHY. Otherwise, the PCIe controller will not work.

[kwilczynski: drop the proprietary firmware conversion comment]
Link: https://lore.kernel.org/linux-pci/20240611125057.1232873-5-yoshihiro.shimoda.uh@renesas.com
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>