These changes are designed to standardize the memory management across
'virt64' and 'c906', ensuring efficient handling of address spaces and
page tables.
Changes:
- Creation of ASID management files (`asid.c`) for both 'c906' and
'virt64' architectures, which is essential for maintaining stability.
- Extensive updates to the MMU configuration and handling in `mmu.c` and `mmu.h` files.
- Addition of functions to manage ASID allocation and switching of page tables.
- For c906, accommodated the early memory setup to the one from virt64.
Signed-off-by: Shell <smokewood@qq.com>