riscv: Introduce NAPOT field to PTDUMP

This patch introduces the NAPOT field to PTDUMP, allowing it
to display the letter "N" for pages that have the 63rd bit set.

Signed-off-by: Yu Chien Peter Lin <peterlin@andestech.com>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Tested-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20230921025022.3989723-4-peterlin@andestech.com


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