Merge branch 'for-linus-4.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml

Pull UML update from Richard Weinberger:
 "A performance enhancement for UML's block driver"

* 'for-linus-4.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml:
  um: UBD Improvements