arm64: defconfig: Enable R-Car PCIe endpoint driver

arm64: defconfig: Enable R-Car PCIe endpoint driver

Enable R-Car PCIe endpoint driver on RZ/G2E board, including enabling
endpoint configurations CONFIG_PCI_ENDPOINT, CONFIG_PCI_ENDPOINT_CONFIGFS,
CONFIG_PCI_EPF_TEST and CONFIG_PCI_ENDPOINT_TEST required to use and test
the driver.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20200811140357.564-1-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>