mm: Remove the vma linked list

mm: Remove the vma linked list

Replace any vm_next use with vma_next().

Update free_pgtables(), unmap_vmas(), and zap_page_range() to use the
maple tree.

Use the new free_pgtables() and unmap_vmas() in do_mas_align_munmap().
At the same time, alter the loop to be more compact.

Now that free_pgtables() and unmap_vmas() take a maple tree as an
argument, rearrange do_mas_align_munmap() to use the new table to hold
the lock

Remove __vma_link_list() and __vma_unlink_list() as they are exclusively
used to update the linked list

Rework validation of tree as it was depending on the linked list.

Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>