riscv: Introduce configuration for 64bit version Microblaze V

The commit 7576ab2facae ("riscv: Add support for AMD/Xilinx MicroBlaze V")
added support for 32bit version. 64bit version is also available that's why
wire it up too.
DT is providing description for generic QEMU target.

Signed-off-by: Michal Simek <michal.simek@amd.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
4 files changed