riscv: Backport request for mmap address space fixes to 6.6

[Vivian Wang]

Hi,

I would like to request backport of these two commits to 6.6.y:

b5b4287accd702f562a49a60b10dbfaf7d40270f ("riscv: mm: Use hint address in mmap if available")
2116988d5372aec51f8c4fb85bf8e305ecda47a0 ("riscv: mm: Do not restrict mmap address based on hint")

Together, they amount to disabling arch_get_mmap_end and
arch_get_mmap_base for riscv.

I would like to note that the first patch conflicts with commit
724103429a2d ("riscv: mm: Fixup compat arch_get_mmap_end") in the stable
linux-6.6.y branch. STACK_TOP_MAX should end up as TASK_SIZE, *not*
TASK_SIZE_64.

Thanks,
Vivian "dramforever" Wang