To determine pgtable level at boot time, we can not use helper functions
in include/asm-generic/pgtable-nop4d.h and must implement these
functions. This patch uses pgtable_l5_enabled variable instead of
including pgtable-nop4d.h to controle p4d's folding, and implements
corresponding helper functions.
Signed-off-by: NQinglin Pan <panqinglin2020@iscas.ac.cn>
Signed-off-by: NPalmer Dabbelt <palmer@rivosinc.com>