Pull UBI and UBIFS updates from Richard Weinberger:
"Minor bug fixes and improvements"
* tag 'tags/upstream-4.17-rc1' of git://git.infradead.org/linux-ubifs:
ubi: Reject MLC NAND
ubifs: Remove useless parameter of lpt_heap_replace
ubifs: Constify struct ubifs_lprops in scan_for_leb_for_idx
ubifs: remove unnecessary assignment
ubi: Fix error for write access
ubi: fastmap: Don't flush fastmap work on detach
ubifs: Check ubifs_wbuf_sync() return code