move mmu_sv32 and mmu_sv39, move bootrom, update path

Created by: sjthales

Command make fpga works for cv32a6 and cv64a6. That was tested by running Linux 32b and 64b. However, for cv32a6 riscv_pkg need to be modified.

I suggest to have 2 new targets in Makefile , fpga_cv64a6 and fpga_cv32a6.