ANDROID: KVM: arm64: Expose unmap_module_page to modules

As modules can already call map_module_page, allows the unmap
counter-part. While at it add a range, so we have the following module
callbacks:

  * map_module_page()    /* legacy */
  * map_module_pages()   /* new callback with a range */
  * unmap_module_pages() /* new callback with a range */

Bug: 357781595
Bug: 447567445
Change-Id: I4f738f1ee01779df702a553b4100252216aa1ab1
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>