ACPI: RISCV: Make acpi_numa_get_nid() to be static

acpi_numa_get_nid() is only called in acpi_numa.c for riscv,
no need to add it in head file, so make it static and remove
related functions in the asm/acpi.h.

Spotted by doing some cleanup for arm64 ACPI.

Signed-off-by: Hanjun Guo <guohanjun@huawei.com>
Reviewed-by: Haibo Xu <haibo1.xu@intel.com>
Link: https://lore.kernel.org/r/20240811031804.3347298-1-guohanjun@huawei.com


Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>