ARM: shmobile: defconfig: Refresh for v5.7-rc1

Update the defconfig for Renesas ARM boards:
  - Enable CONFIG_DRM_DISPLAY_CONNECTOR (for HDMI, VGA, and composite
    display connectors on various R-Car H1, Gen2, and RZ/G1 boards,
    since commit 0c275c30 ("drm/bridge: Add bridge driver for
    display connectors")).

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20200415124923.2510-1-geert+renesas@glider.be