loongarch: Implement the new page table range API

loongarch: Implement the new page table range API

Add update_mmu_cache_range() and change _PFN_SHIFT to PFN_PTE_SHIFT.
It would probably be more efficient to implement __update_tlb() by
flushing the entire folio instead of calling __update_tlb() N times,
but I'll leave that for someone who understands the architecture better.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: loongarch@lists.linux.dev