riscv: mm: Return intended SATP mode for noXlvl options

riscv: mm: Return intended SATP mode for noXlvl options

Change the return value of match_noXlvl() to return the SATP mode that
will be used, rather than the mode being disabled. This enables unified
logic for return value judgement with the function that obtains mmu-type
from the fdt, avoiding extra conversion. This only changes the naming,
with no functional impact.

Signed-off-by: Junhui Liu <junhui.liu@pigmoral.tech>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Nutty Liu <liujingqi@lanxincomputing.com>
Link: https://lore.kernel.org/r/20250722-satp-from-fdt-v1-1-5ba22218fa5f@pigmoral.tech
Signed-off-by: Paul Walmsley <pjw@kernel.org>