ARM: configs: Update Realview defconfig

Update the Integrator defconfig to the changes from the recent
kernel cycles and especially the v5.9-rc1 changes.

- Move options around as a result of Kconfig changes.
- Drop the ZBOOT_ROM* stuff that doesn't exist anymore.
- Add the syscon LEDs as used on the board for heartbeat
  and MMC traffic indication.
- Add fixed voltage regulator support, this is used by the
  MMC controller for card voltage.
- Select CONFIG_DRM_DISPLAY_CONNECTOR=y, the
  CONFIG_DRM_SIMPLE_BRIDGE was renamed when renaming the
  driver, but the simple bridge requires another bridge,
  the display connector bridge, in order to work, so this
  is required to have graphics working properly in kernel
  v5.9-rc1+

Link: https://lore.kernel.org/r/20200901082558.80388-1-linus.walleij@linaro.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Olof Johansson <olof@lixom.net>