ARM: ep93xx: remove memory configuration options

The ARM_PATCH_PHYS_VIRT option makes the ep93xx memory configuration
options obsolete.

This allows support for all the ep93xx variations to be built into a
single kernel.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>