Merge branch 'asm-generic-io.h-cleanup' into asm-generic

MIPS is the last architecture that is yet to start using asm-generic/io.h,
so Baoquan He converts it, which allows the other changes to remove code
duplication, and it will allow further cleanups in the future.

* asm-generic-io.h-cleanup:
  asm/io: remove unnecessary xlate_dev_mem_ptr() and unxlate_dev_mem_ptr()
  mips: io: remove duplicated codes
  arch/*/io.h: remove ioremap_uc in some architectures
  mips: add <asm-generic/io.h> including