PCI: Drop PCIE_RCAR config option

All the defconfig files have replaced PCIE_RCAR config option with
PCIE_RCAR_HOST config option which built the same driver, so we can
now safely drop PCIE_RCAR config option.

Link: https://lore.kernel.org/r/20201229170848.18482-1-prabhakar.mahadev-lad.rj@bp.renesas.com


Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>