ARM: versatile: Remove Integrator and Realview from PHYS_OFFSET

Both Integrator and Realview exclusively use
ARM_PATCH_PHYS_VIRT these days so drop them from the
PHYS_OFFSET Kconfig option.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20200814154529.3487163-1-linus.walleij@linaro.org