mm/mmap: use advanced maple tree API for mmap_region()

mm/mmap: use advanced maple tree API for mmap_region()

Changing mmap_region() to use the maple tree state and the advanced maple
tree interface allows for a lot less tree walking.

This change removes the last caller of munmap_vma_range(), so drop this
unused function.

Add vma_expand() to expand a VMA if possible by doing the necessary
hugepage check, uprobe_munmap of files, dcache flush, modifications then
undoing the detaches, etc.

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