This patch adds the bindings for the R-Car PCIe endpoint driver.

Link: https://lore.kernel.org/r/1588854799-13710-7-git-send-email-prabhakar.mahadev-lad.rj@bp.renesas.comSigned-off-by: NLad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: NRob Herring <robh@kernel.org>
Reviewed-by: NYoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>