arm64: pgd: Mark pgd_cache as __ro_after_init

pgd_cache is setup once while init stage and never changed after
that, so it is good candidate for __ro_after_init

Signed-off-by: Jinbum Park <jinb.park7@gmail.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
1 file changed