armv8: K3: j7200: Add custom MMU support

armv8: K3: j7200: Add custom MMU support

The A72 U-Boot code can load and boot a number of the available
R5FSS Cores on the J7200 SoC. Change the memory attributes for the
DDR regions used by the remote processors so that the cores can see
and execute the proper code.

The J7200 SoC has less number of remote processors compared to J721E,
so use less memory for the remote processors. So, a separate table
based on the current J721E table is added for J7200 SoCs, and selected
using the appropriate Kconfig CONFIG_TARGET_J7200_A72_EVM symbol.

Signed-off-by: Suman Anna <s-anna@ti.com>