Merge back from docs-next in order to get the cdomain extension.

With such extension, the number of warnings when building docs
in nitpick mode reduced from 22 to 2 warnings.

* docs-next/docs-next:
  docs/driver-model: fix typo
  DMA-API-HOWTO: <asm/generic/scatterlist.h> is no more
  doc-rst:c-domain: function-like macros arguments
  doc-rst:c-domain: fix sphinx version incompatibility
  Documentation/filesystems: Fixed typo
  docs: Don't format internal MPT docs
  docs: split up serial-interfaces.rst
  docs: Pull the HSI documentation together
  docs: Special-case function-pointer parameters in kernel-doc
  docs: make kernel-doc handle varargs properly
  x86: fix memory ranges in mm documentation
  documentation/scsi: Remove nodisconnect parameter
  doc: ioctl: Add some clarifications to botching-up-ioctls
  docs: split up the driver book
  Docs: sphinxify device-drivers.tmpl