ARM: shmobile: defconfig: Refresh for v5.8-rc1

Refresh the defconfig for Renesas ARM boards:
  - Drop CONFIG_ZBOOT_ROM_TEXT=0x0 CONFIG_ZBOOT_ROM_BSS=0x0 (no longer
    needed since commit 39c3e304 ("ARM: 8984/1: Kconfig: set
    default ZBOOT_ROM_TEXT/BSS value to 0x0")),
  - Move CONFIG_MEDIA_SUBDRV_AUTOSELECT (moved in commit
    1b80d36a ("media: Kconfig: move the position of sub-driver
    autoselection")),
  - Drop CONFIG_MEDIA_CONTROLLER=y and CONFIG_VIDEO_V4L2_SUBDEV_API=y
    (auto-enabled since commit 32a363d0 ("media: Kconfig files:
    use select for V4L2 subdevs and MC")),
  - Enable CONFIG_MEDIA_PLATFORM_SUPPORT (needed since commit
    06b93644 ("media: Kconfig: add an option to filter in/out
    platform drivers")).

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20200624131931.3686-2-geert+renesas@glider.be